Chapter Two. Cisco Router Hardware
The Cisco router product line has three flavors. Cisco routers are available as modular, fixed or combination configurations. Along with full router configuration Cisco offers router platforms on personal computer (PC) card format. Additionally, Cisco combines routers and small hubs into one device suitable for small office installations. Key to a successful implementation of Cisco routers in a networking environment is proper placement and configuration of the router. Each Cisco router offering is suited for a specific function. These functions are depicted in Figure 2.1 as core, distribution and access. These functional characteristics make up Ciscos router internetwork architecture.
The 12000 series router platform is built in support of providing gigabit (Gb) speeds across WAN and MAN backbones. The Cisco 12000 series is targeted at scaling Internet and enterprise backbones at speeds up to 2.4 Gbps. This is the aggregate bandwidth of an OC-48 SONET connection. The Cisco 12000 series is optimized for IP only networks and thereby provides a high-speed backbone infrastructure for IP based networks. The ability to handle OC-3 through OC-48 SONET connections enables network engineers to expand the backbone switching capacity with a range from 5 to 60 Gbps. Since the 12000 eries is built for providing core backbone it is designed for maximum uptime and minimal disruption. These features are found in the its architeture for:
The speeds of the Cisco 12000 series routers is possible from the synchronized circuitry of two cards. The Clock and scheduler card (CSC) and the Switch Fabric Card (SFC). Both the CSC and SFC provide an OC-12 switching bandwidth between the line cards for the system. Each type of card has a switching capacity of 15 Gbps.
A minimum of one CSC is required in the router. The CSC performs the following functions for the router:
The Switch Fabric Card provides the following functionality for the router:
The chassis configuration of the Cisco 12000 router comes with an upper cage and lower cage. The upper cage is used mostly for the line cards to connect to the network in addition to the Gigabit Route Processor (GRP) card. The lower cage supplements the ability for the 12000 series router to perform switching by having extra slots for the SFC installs. For more information on the specific cage configurations of the 12000 series router consult the section specific to the model.
The 12000 series comes in three models. These are the 12004, 12008 and 12012.
The 12000 series is placed at the very core of the network. Since it is optimized for IP traffic it must be designed that IP traffic only flows through these routers. For example, in a network that is based on IP and SNA the SNA data must be transported using RSRB or DLSw+ with TCP or FST encapsulation techniques. In this manner, the high speed backbone can be used for connecting remote locations to the main data centers. Likewise, using Voice over IP the router or PBX must encapsulate the voice data into IP prior to delivering it to the 12000 series backbone routers. Based on this type of usage the 12000 series is ideal for:
Each line card is comprised of several functions equivalent on each card. The line card uses for burst buffers to prevent packet dropping when there is an instantaneous increase in back-to-back small packets queued for transmission. Burst buffers increase throughput and maintain an even packet burst for packets arriving on Layer 3 switch processing.
Each line card contains two silicon queuing engines one for receive and one for transmit. The receiving engine moves packets form burst buffers to the switch fabric. The transmit moves the packets from the switch fabric to the transmit interface. The silicon engines also manages the movement of IP packets in buffer memory. Buffer memory defaults to 32 MB split evenly between receive and transmit buffers. The amount of buffer memory in use is configurable up to 64 MB for receive and 64 MB for transmit.
An application-specific integrated circuit (ASIC) is used for supporting the high-speed process required to perform layer 2 switching. To assist in the decision making an IDT R5000 200 MHz RISC processor is on the line card to make forwarding decisions based on the Cisco Express Forwarding table and the Layer 2 and Layer 3 information in the packet. The GRP is constantly updating the table based on information gathered from the routing table.
The line card also contains a switch fabric interface. This is the same 1.25 Gbps full-duplex data path used by the GRP. When a packet is on the proper queue the switch fabric requests the CSC for scheduling the transfer of the packet across the switching fabric.
There is also a maintenance bus module on the line card that provides the master Mbus module of the GRP with requested information. The type of information reported in temperature, and voltage. In addition the Mbus on the line card stores the serial number, hardware revision level and other pertinent information about the card in EEPROM.
In addition each line card maintains the Cisco Express Forwarding (CEF) table. The table is built on routing table information provided by the GRP and is used to make forwarding decisions.
There are six available line cards for connecting the 12000 series router to the network. These are:
The Quad OC-3c/STM-1c Packet-Over-SONET (POS) is shown in Figure 2.6
. The card has four ports for interfacing directly to the SONET providers equipment. The Quad OC-3c/STM-1c Packet-Over-SONET (POS) line card must be ordered for either single mode or multimode SC fiber connection. Each mode supports full-duplex transmission. The card uses for 128 KB burst buffers to prevent packet dropping when there is an instantaneous increase in back-to-back small packets queued for transmission.
The Quad OC-3 ATM Line Card shown in Figure 2.7 (h10781) performs ATM segmentation and Reassembly functions for ATM connectivity. Segmentation is the process of converting packets to ATM cells. Reassembly is the process of converting ATM cells to packets. The Quad OC-3 ATM Line Card can handle up to 4000 simultaneous reassemblies of an average packet size of 280 bytes. To perform this ability the Segmentation and Reassembly is performed on ASIC. The ASICs also allow each of the four ports on the Quad OC-3 ATM Line Card to support 2000 active virtual circuits. The card must be ordered as either single mode or multimode fiber connection. The Quad OC-3 ATM Line Card supports a burst buffer of 4 MB.
The OC-12c/STM-4c Packet-Over-SONET (POS) illustrated in Figure 2.8 (h10782.gif) has a one duplex SC single- or multimode fiber connection. The port supports OC-12c at 622 Mbps data rate. The OC-12c/STM-4c Packet-Over-SONET (POS) has a burst buffer of 512 KB.
The OC-48c/STM 16 Optical IP Interface Card shown in Figure 2.9 (15424.gif) a single duplex SC or FC single mode fiber connection. The top port is the transmit (TX) connection and the bottom port is the receive (RX) connection. The interface supports a full 2.5 Gbps optimized for transporting packet over SONET (POS). The burst buffer on the OC-48c/STM-16 Optical Interface Card is 512 KB with a default buffer memory of 32 MB for receive and 32 MB for transmit. Cisco IOS software Release 11.2(14)GS1 and line card microcode Version 1.14 is required for complete support of all features. The typical maximum distance the line card can sustain is 1.2miles or 2 kilometers.
The Channelized OC-12 Line Card shown in Figure 2.10 (11704.gif) supports only single mode full-duplex SC connections at 622 Mbps. Its burst buffer size is 512 KB. The forwarding processor on the Channelized OC-12 Line Card is an IDT R5000 RISC processor rated a 250 MHz.
The Cisco IOS software for the Cisco 12000 series routers is optimized for transporting IP traffic. The first release of Cisco IOS supporting the Cisco 12000 series platform is the 11.2 release. The Cisco IOS Release 11.2 supports the following IP IOS functions:
Interior: RIP, OSPF, IS-IS, ISO/CLNP, EIGRP, EGP
MED (Multi-Exit Discriminators)
DPA (Destination Preference Attribute)
Flat/Weighted Route Dampening
Static Routing (IGP)
SNMP, Telnet, MIB II
Memory on the RSP and any interface processor is paramount to efficiently running the routers. The more the better. It does not hurt to order the highest amount of memory available for any platform as an inexpensive insurance policy against poor design or "memory leaks" from the IOS or microcode software. That aside, the 7500 series platform comes with DRAM memory size recommendations based on the number of IP routes in a network. Cisco categorizes network sizes into the following:
The for the RSP1, RSP2 and RSP4 system processors on each on the 7505, 7507 and 7513 router platform the DRAM memory requirements are recommended to be:
Cisco highly recommends that even if some networks are much smaller than the 2,000 IP routes a minimum of 32MB of DRAM is beneficial for router performance.
The Flash memory PCMCIA cards available for insertion into slot 0 and slot 1 of the RSP boards are available in different memory sizes. The default card comes with 8MB of memory and has a default IOS software image stored. If a spare is ordered or purchased it must first be formatted before use. PCMCIA cards used on RP boards from a 7000 series router must be reformatted for use on the 7500 series router due to a difference in formatting of memory on the different system processors.
On introduction of the 7000 platform Cisco used a Motorola 68040 CPU clocked at 25Mhz.. While this was considered fast for the time it has since been antiquated. The CPU is found on the Router Processor (RP) board. The RP is installed in slot 6 of the 7000 series and slot 4 of the 7010 series. In concert with the RP, the 7000 platform utilized three models of a Switch Processor (SP). These are the Switch Processor (SP) Silicon Switch Processor (SSP) and Silicon Switch ProcessorŠ2MB (SSP-2MB). The SP offloaded the responsibility of managing the CxBus from the CPU on the RP board. Thus, allowing the RP to efficiently manage system functions. Further enhancements using a Silicon Switch Engine (SSE) on the SP allowed the SP to examine incoming packet data link and network link header information making an intelligent decision on whether the packet should be bridged or routed and forward the packet to the corresponding interface. The speed of the decision process was enabled by using a silicon-switching cache which kept track of packet information through the router. The SSE is encoded in the SP hardware and in this configuration is called a Silicon Switch Processor (SSP). The SSP performs switching decisions independently of the RP thereby increasing the throughput and efficiency of system resources. The base SSP includes an extra 512KB of memory for handling switching decisions while the SSP-2MB provides an extra 2MB of memory. On the 7000 series the SP, SSP or SSP-2MB is installed in slot 5 and on the 7010 series the SP, SSP or SSP-2MB is installed in slot 3. The configuration for this installation is shown in Figure 2.19.
Extending the life of the 7000 platform was made possible by the introduction of the Route Switch Processor 7000 (RSP7000) and the 7000 Chassis Interface (7000CI) processors. These two boards together give the 7000 platform the enhancements and ability to use the IOS software made for the 7500 router platform. The IOS software must be at IOS version 10.3(9), 11.0(6) 11.1(1) or later to support the RSP7000 processor and the 7000CI processor. The RSP7000 increases the performance of the 7000 platform by using a MIPS Reduced Instruction Set Code (RISC) CPU at 100MHz and a bus speed clocking (external clock) of 50Mhz. Use of the RSP7000 on the 7000 and 7010 series routers enables these platforms to use the Versatile Interface Processor (VIP) technology supported under the 7500 IOS software platform. The 7000CI monitors chassis specific functions relieving the RSP7000 from the following duties:
The RSP7000 is installed in slot 5 of the 7000 series and slot 4 of the 7010 series. The 7000CI is installed in slot 6 of the 7000 series and slot3 of the 7010 series. Figure 2.20 diagrams the installation of the RSP7000 and 7000CI on both the 7000 and 7010 series routers.
While both the RP and RSP7000 use the Intel Series 2+ Flash Memory cards, they must be reformatted if used between the two processors. The RP supports one slot for flash memory and the RSP7000 supports two flash memory slots. The RP flash memory PCMCIA card is either 8MB or 16MB. The RSP7000 is available in either 8-, 16- or 20MB formats with a total of 40MB of flash memory.
The RP processor comes standard with 16MB of RAM and is upgradeable to 64MB. The RSP7000 comes standard with 32MB of RAM with expansion to a total of 128MB. Appendix D highlights the various DRAM requirements along with the feature sets available for the 7000 series routers.
The AIP board supports fiber optic connectivity and coaxial connectivity in support of Asynchronous Transfer Mode (ATM) networking environments. The board also supports single mode and multimode fiber-optic connections. Figure 2.21 illustrates the AIP board with a fiber-optic PLIM. The following lists the media types supported by the AIP board:
The AIP board can now support up to OC-12 SONET connectivity for high bandwidth and throughput requirements. Each of the media type supported requires a specific cable connection. Appendix E lists all the cable specifications for all the router platforms and their interfaces.
The Cisco Channel Interface Processor 2 (CIP2) is the second generation of IBM mainframe channel connectivity boards offered in support of connecting router networks directly to the mainframe. The CIP2 is a direct competitor to IBMs 3172 Interconnect Controller and the IBM 2216 channel attached router. The CIP2 has memory and processing advantages over the first generation CIP. The CIP2 supports both IBMs parallel bus-and-tag channel and ESCON fiber channel architectures. The CIP2 ships with a default of 32 MB of memory with memory configuration of 64- and 128-MB allocations.
The CIP2 is compatible with the Cisco 7000 series router using Cisco IOS release 10.2(13) or later, 10.3(12) or later, 11.0(10) or later and all versions at 11.1(5) or later. The 7500 series router requires the Cisco IOS release level be at 10.3(13) or later, 11.0(10) or later, and all versions at 11.1(5) or later.
The CIP2 microcode is unbundled from the IOS software as of release 11.1(7) and must be ordered separately from the IOS when installing a CIP2. The microcode supports the following mainframe connectivity features:
The CIP2 supports different combinations of channel connectivity to the mainframe. These combinations are configured at the factory and must be ordered appropriately. Figure 2.22 diagrams a CIP2 board with a single parallel channel and single ESCON interface configuration. The valid combinations for the CIP2 interfaces are:
When ordering a CIP2 board it is advisable to determine the number of TCP/IP and SNA connections planned for use by the CIP2. The number of connections directly related to CIP2 performance and memory requirements. While Cisco has memory recommendations and formulas to calculate memory requirements it is advisable to order the CIP2 with the maximum amount of memory, 128 MB, to allow for growth and performance without compromising availability and reliability. Appendix E details the CIP2 memory formulas and minimum requirements.
The FIP enables the Cisco 7000 and 7500 router platform to support single mode and multimode FDDI connections at 100 Mbps. Figure 2.26 diagrams the four FIP board configurations. These configurations support:
The MIP, shown in Figure 2.29, is a multichannel multiplexer allowing the router to emulate an Nx64 or Nx56 backbone multiplexer on a 1.536 Mbps (T1) or 2.048 Mbps (E1) line. The MIP supports seven different types of configurations:
These configuration allow the MIP to provide varied answers to connectivity requirements. The dual port MIP can act as a dial-on-demand ISDN PRI for high volume locations or be configured through software enabling one port to act as an ISDN PRI line while the other operates as a multichannel multiplexer feeding remote locations.
The POSIP board, shown in Figure 2.30, complies with RFC 1619, "PPP over SONET/SDH" and RFC 1662, "PPP in HDLC-like Framing". Using these standards, the POSIP encapsulates packet data using Point-to-Point Protocol (PPP) which is then mapped into an STS-3c/STM-1 frame reducing the transport overhead by approximately fifty percent as compared to using ATM adaptation Layer 5 (AAL5) and line card control (LCC) Subnetwork Access Protocol (SNAP) encapsulations over SONET OC-3 media.
The POSIP interface supports one 155 Mbps port using either single-mode or multimode optical-fiber on Cisco 7000 and 7500 series routers. The Cisco 7000 must have the RSP7000 system processor installed to support the POSIP board. The POSIP has support for the following features:
The POSIP board connects the OC-3 optical-fiber network to the CxBus on the 7000 series or the CyBus on the 7500 series routers. The POSIP installs on any available interface processor slot. The POSIP board may be configured with 16 or 32 MB of DRAM and 1 or 2 MB of SRAM. The memory requirements may be upgraded at a later date.
Internet Service Providers require speed in delivering packets between the end user community and the Internet. The SMIP functions similarly to the MIP. However, the SMIP does not support multiprotocol routing. Using Cisco IOS Release 10.2(6) or later is requried to support the following SMIP functions:
The SMIP, shown in Figure 2.31, supports three different types of configurations. These are:
Note that the SMIP is only optioned with two ports. One port may be used to channelize Nx64 or Nx56 supporting 24 channels on a T1 or 30 channels on an E1. Each channel is configured as its own serial interface. The second port may be used as an ISDN PRI port for ISDN BRI dial connections to the router.
The VIP2, shown in Figure 2.34, is a new generation interface processor board with a high speed RISC MIPS 4700 processor with an internal speed of 100 MHz and a system bus interface speed of 50 MHz. This CPU enables the VIP2 to process all functions on the VIP2 rather than requesting functions from the RSP system processor. This function is available with Cisco IOS Release 11.1(472) or later, enabling the VIP2 to run the Cisco IOS kernel directly on its own CPU. The 7000 and 7010 series routers must have the RSP7000 and 7000CI system boards installed in order to use the VIP2 features.
The VIP2 is comprised of a motherboard and up to two port adapters or service adapters. Any combination of port or service adapters may be installed on the VIP2 in support of LAN and WAN interfaces and services. Appendix E details the VIP2 models of VIP2 required in support of various port adapter and service adapter configurations.
The port and service adapters for the 7x00 series routers are compatible between the VIP2 and the 7200 series router. The 7000 and 7010 series routers must have the RSP7000 and 7000CI system boards installed prior to using the VIP2 board supporting the port adapter and service adapters. The following media and interface types are supported on the entire 7x00 series product line:
The Cisco 7200 series supports all of the above media and interface types along with support for ATM-Circuit Emulation Services (ATM-CES) and ISDN PRI and BRI connections.
The synchronous serial port adapter comes with four interfaces. Each interface must be alike and supports the following electric standards:
The interfaces support either DCE or DTE terminations depending on the type of cable connected to the interface. The synchronous serial port adapter depicted in Figure 2.44 is available on the Cisco 7500, 7000 and 7200 series routers.
Bandwidth for many installation is a valuable asset. Compressing data prior to transmission enables routers to transmit fore information than would be allowed without compression. The Compression Service adapters off-load compression and decompression functions from the host processor for inbound and outbound traffic over channelized E1/ISDN PRI, channelized T1/ISDN PRI, BRI ISDN and synchronous serial port adapters. Figure 2.50 diagrams the two models for the compression service adapters.
The first model has 786 KB of memory enabling it to handle compression/decompression for up to 64 WAN links. The second model is configured with 3 MB of memory in support of 256 WAN links. Both models of the compression service adapter are available on the entire Cisco 7x00 family of routers.
The Cisco 4x00 router platform is based on the use of network processor modules (NPM). Using the NPMs a 4x00 router can combine many different types of interface connections in support of various networking requirements. The 4x00 series router platform is available in three models. Each model looks identical as depicted in Figure 2.51, with different interface support and processing power. The models 4000-M, 4500-M and 4700-M can mix and match the NPMs using the three available slots. The low-end 4000-M model supports the following NPMs:
The higher-end 4500-M and 4700-M routers support the following network interfaces in any combination using the three available slots:
The NPMs available for each router platform come in various port configurations. Though some have multiple ports the 4000 series platform supports full wire speed on each port. Each NPM has the following port configurations:
Due to the processing of the high-speed NPMs there is a maximum of two high-speed interface available on the Cisco 4500-M and Cisco 4700-M platforms. This means only two of the following NPMs may be installed and operable using the Fast Ethernet, FDDI, ATM-OC3 or DS-3 NPMs. The exception to this is that there can only be one ATM-OC3 NPM configured and operable on the 4500-M or 4700-M routers. Therefore combinations with the ATM-OC3 NPM are either one Fast Ethernet, one FDDI, one ATM-DS3 or E3, and one HSSI. The 4500 or 4700 routers can however be configured with two Fast Ethernet, two FDDI, two HSSI, or one Fast Ethernet and one FDDI, or one Fast Ethernet and one HSSI, or one FDDI and one HSSI. In these types of configuration the remaining slot may be used by the other NPMs as noted. For complete detail of NPM configurations and combinations see Appendix F.
Each 4000 series router comes standard with 128 KB of NVRAM which is used to store and recall the router configuration. Main memory on the router is used for executing the Cisco IOS and process routing tables. Shared memory is used to move packets between interfaces and flash memory is used to store router configurations and Cisco IOS code. Since the 4000 series is actually designed for the access layer of the Cisco routing architecture it comes with low base memory.
The 4000-M platform comes with a base of 4 MB of Flash memory expandable to either 8 MB or 16 MB. Main memory on the 4000-M starts with 8 MB and may be expanded to 16 or 32 MB of memory. Shared memory on the 4000-M in earlier models were shipped with 1 MB of shared memory. The newer models are shipped with 4 MB of shared memory. If the 4000-M being used is an earlier model the shared memory must be upgraded to a minimum of 4 MB to support FDDI or have more the five physical or virtual interfaces defined. Shared memory is expandable to 16MB.
The Flash memory support on the 4500-M platform is the same as that found on the 4000-M router. Main memory comes standard at 16 MB and with an upgrade to 32 MB of main memory. The 4500-M router comes standard with 4 MB of shared memory with the option to expand to 8 or 16 MB.
The 4700-M platform also comes standard with 4 MB of flash memory with upgrades to either 8 or 16 MB. Being the high end of the 4000 series platform the 4700-M comes standard with 16 MB of main memory with expansion to either 32 or 64MB of memory to handle large routing tables. Shared memory on the 4700-M is the same as that found on the 4500-M router.
The 3600 series routers is one of the newer modular platforms form Cisco. This router comes in two models the 3640 and the 3620. The 3600 series provides for increased dial-up port density with newer WAN technologies like ATM. One special feature available on the 3600 series is the ability for the operator console and auxiliary console to connect to a local or remote PC at 115.2 Kbps and support for Xmodem or Ymodem protocol for loading the router IOS software directly through these ports versus having to have a network connection.
The 3640 has more port capacity than the 3620 as shown in Figure 2.53. The 3640 is available with four network module slots while the 3620 has two network module slots available. The module slots are used to connect external media to the bus backplane of the router with network module interface cards that mix LAN and WAN media types along with asynchronous and synchronous serial connections and support for ISDN PRI and BRI interfaces.
In support of ISDN PRI connectivity the 3640 installed with a mixed media module and three 2-port ISDN PRIN network module interface can connect up to 138 T1 or 180 (E1) B channels. This enables the 3640 as a cost effective solutions for corporate telecommuting. Using three 8-port ISDN BRI network interface modules the Cisco 3640 connects up to 48 B channels with local LAN and WAN routing capability.
The port density on the network interface cards enables the 3640 to support up to 24 asynchronous or synchronous serial interfaces for multiple 56 Kbps connections. The 3600 series routers support the following network interfaces:
The 3600 series of Cisco routers require Cisco IOS software Release 11.1(7)AA and later or Release 11.2(5)P and later.
The network modules are the cards that slide into the slots of the 3600 series routers as shown in Figure 2.54. The network modules themselves provide various interfaces for connecting external networks to the router bus backplane. Of these network modules one of the more versatile is the mixed-media network module.
The mixed-media network module supports up to two fixed LAN interfaces and two user installable WAN interfaces. The LAN interfaces are a part of the network module itself and cannot be removed. The LAN interface support as illustrated in Figure 2.55 is one of the following:
The Ethernet connections support both 10BaseT and AUI interfaces at 10 Mbps. The Token Ring port is either 4 or 16 Mbps using either STP or UTP wiring. The WAN expansion slots on the mixed-media network module supports the following WAN interface cards:
Each of the WAN network interface cards are shown in Figure 2.56. The Cisco 1600 series routers also supports the Cisco 3600 ISDN BRI, ISDN with NT1 and serial interface cards. The 3600 series router requires Cisco IOS Release 11.2(4)XA, 11.2(5)P or later to properly operate the WAN interface cards ISDN BRI, ISDN with NT1, 1-port 4-wire 56 Kbps DSU/CSU interface cards.
The network modules supporting channelized T1/E1 and ISDN PRI lines are available with a built-in CSU with one or two ports. Figure 2.57 illustrates the various channelized T1/ISDN-PRI and E1/ISDN-PRI network modules available for the 3600 series routers. Using a T1/ISDN-PRI CSU the network module connects directly to the providers network connection. Without the internal CSU the T1/ISDN PRI network module connects to an external CSU which then connects to the provides network connection. The T1 module channelizes the T1 up to 24 virtual channels per T1 port. The E1/ISDN PRI network module provides one or two E1 ports at 2.048 Mbps second in full duplex transmission. They are configured as either balanced or unbalanced and provide up to 30 virtual channels per E1 port. If the T1/E! modules are configured for using ISDN PRI they are not compatible with the 4 or 8-port ISDN BRI modules. However, when used as a "multiplexer" the ISDN BRI modules are compatible.
The ISDN BRI network modules have four different models. The use of 4 or 8 ISDN BRI ports along with S/T or on board NT1 service for each port define the four different model types as shown in Figure 2.58. The ISDN BRI network modules use local SRAM for buffer descriptor, input queues and configuration storage to increase performance. The performance of the ISND BRI 8-port model is 5,760 packet-per-second (pps) running full-duplex continuous data of 144 Kbps using 50-byte packets. The aggregate full duplex rate of the 8-port ISDN BTI network module is 2.3 Mbps. The ISDN BRI network modules include features to query the network module, SNMP traps for monitoring the network module, manageability with Ciscoworks or CiscoView and support for the ISDN MIB standard.
For more traditional low-speed network connections the 4 and 8-port Asynchronous/Synchronous network modules are available. Figure 2.59 illustrates the two module formats. These network modules support 128 Kbps synchronous connections or 115.2 Kbps asynchronous connections per port. The ports use the DB-60 interface standard for connecting to the router.
In support of Ethernet the 3600 series network modules are available with 1 and 4-port Ethernet connections. As shown in Figure 2.60, the 1-port Ethernet network module comes with one AUI DB-15 and one 10BaseT RJ-45 interface connections. Only one of these ports may be active at any time for this network module. The 4-port Ethernet adds to the 1-port Ethernet network module format three 10BaseT RJ-45 connections on the left side of the network module. The restriction of either the AUI or RJ-45 port be active on the right side of the 4-port Ethernet module still holds true. Cisco IOS Release level 11.2(4)XA and 11.2(5)P or later are required for operation.
The advancement of Ethernet has dictated that the network modules keeping with the new Ethernet standards. Currently, the 3600 series routers support a 1-port Fast Ethernet network module using an RJ-45 connector or a 40-pin media-independent interface (MII).. Again, there is a restriction that only one of these interfaces may be active at any given time. The RJ-45 connects two pair Category 5 UTP wiring using the 100BaseTX standard. Using the MII an external transceiver is required to connect to a multimode optical fiber using 100BaseFX standard or it can use the 100BaseT4 standard over four-pair of Category3, 4 or 5 UTP or STP wiring. Figure 2.61 diagrams the 1-port Fast Ethernet network module for the 3600 series router which requires Cisco IOS Release 11.2(6)P or higher for operation.
The Cisco 3640 supports a maximum of two 1-port Fast Ethernet network modules with no other network modules installed. If using the 1-port Fast Ethernet with a 4-port Ethernet network module the 3640 router may be configured for a maximum of 1 Fast Ethernet and two 4-port Ethernet network modules along with other network modules.
Using the high-density DB-60 interface standard the 4-port serial network module can support various data rates. If only port 0 is use then the interface can realize a data rate of 8 Mbps. Using ports 0 and 2 the data rate is halved to 4 Mbps per port and using all four ports the data rate is halved again to maximum of 2 Mbps per port.
The two models of the Cisco 3600 series use different processors. The Cisco 3640: uses the 100-MHz IDT R4700 RISC processor and the Cisco 3620 uses the 80-MHz IDT R4600 RISC processor. The 3600 series uses a single DRAM pool which is partitioned main and shared memory areas. This partitioning of DRAM makes memory calculation difficult when configuring the 3600 router platforms. Appendix F identifies some guidelines on how to configure the proper amount of DRAM for the 3600 routers. The 3600 series also uses flash memory. Both the DRAM and flash using the SIMM chips for memory allowing field upgrades and replacements. The standard flash memory is 4 MB. However, the flash memory can be upgraded to a maximum of 48 MB for both the 3620 and 3640 routers. Each routers comes with a base of 16 MB of DRAM which is expandable on the 3620 to 64 MB and on the 3640 to 128 MB. In addition to on board flash memory the 3600 series has PCMCIA two slots available in support of 4MB to 128 MB of flash using two 64 MB PCMCIA flash cards.
The Cisco 2600 series router platform extends the modular format of the 3600 series into the smaller remote branch office. The modularity of the 2600 series enables these small offices to deploy voice/fax/video along with data in a single versatile network appliance. The Cisco 2600 shares many of the same network module interfaces with the 3600 and 1600 router platforms. The 2600 series supports one network module slot, two WAN Interface Card slots and a new interface slot dubbed Advanced Integration Module (AIM). Cisco maximizes uptime on the 2600series through the use of an external Redundant Power Supply (RPS) and Cisco IOS dial-on demand routing features for the restoration of both data an voice connections automatically should the primary link failure occur.
The 2600 series comes in two flavors: a single Ethernet (2610) or a dual Ethernet interface (2611). The WAN interface card slots support:
The network modules add needed support for:
The AIM slot supports added features for optimization through hardware assisted data compression and encryption.
An auxiliary port with the ability for use as a 115 Kbps Dial ON Demand Routing interface for WAN back-up connectivity is standard on both the 2610 and 2611 models. Figure 2.63 shows the rear panel of the 2600 models.
The Cisco 2600 shares many of the data network modules with the 3600 series routers. These shared data network modules are:
The following Voice/fax network modules and interface cards are shared with the 3600 series router:
The 2600 series also shares WAN Interface Cards (WICs) with the 1600 and 3600 series routers. These cards are the:
WICs unique to the 2600 series support the following configuration:
The system memory (DRAM) comes in two DIMM slots. The default memory size is 16MB with expansion to a total of 64 MB. Flash memory is incorporated on the processor board using a single SIMM slot supporting a default of 4 MB with expansion to 16 MB. The DRAM on the 2600 uses pooled DRAM memory. The DRAM is partitioned between processor and packet memory areas. The default 16 MB of DRAM is partitioned into 12 MB for processor and 4 MB for packet memory.
Cisco IOS Release 11.3(2)XA and 11.3(3)T and higher. The Cisco IOS may be loaded into the router using the LAN interface and TFTP or using the auxiliary or console port using Ymodem or Xmodem protocols. This is valuable for remote dial-up restoration of a damaged IOS or for updating the stored configuration file.
The 2500 series router platform from Cisco provides specific access layer functions for small offices or small business. The 2500 series comes in many different solution formats. These are:
Additionally, the 2500 series comes in an access server offering for supporting remote dial-up access to enterprise networks The Cisco access servers are not discussed in this text. The console and auxiliary ports on the 2500 series use RJ-45 connectors. Any 2500 series model ordered comes with a cable kit to connect an RJ-45-to-RJ-45 using a roll-over console cable, an RJ-45-to-DB-25 male DCE adapter, an RJ-45-to-DB-25 female DTE adapter, and an RJ-45-to-DB-9 female DTE adapter for connecting PCs or modems to the these ports. The low-speed serial asynch-/synchronous ports on all the models support asynchronous connections up to 115.2 Kbps and synchronous connections up to 2 Mbps.
The single LAN routers come in eight models. Each model has a different combination of non-upgradeable or non-field modifiable interfaces. The 2501 shown in Figure 2.65 provides a single Ethernet 10 Mbps port and two synchronous serial interfaces. The Ethernet uses a DB-9 AUI port which may require an external transceiver to connect to an RJ-45 LAN hub interface. The two serial ports use DB-60 connectors and all data rates up to 2 Mbps.
The 2502 router pictured in Figure 2.65 has a token-ring LAN interface instead of an Ethernet AUI port. The token-ring interface uses DB-9 connection which may require a converter to an RJ-45 connector for connecting to a LAN hub. The token Šring interface is configurable as 4 or 16 Mbps data rates.
The addition of a single ISDN BRI port on the is shown on the 2503 and 2504 routers in Figure 2.65. Note that the 2503/2504 is the same as the 2501/2502 with the exception of the ISDN BRI ports. The ISDN BRI ports have an internal ISDN Terminal Adapter. These ports must connect to an ISDN NT1 device for switched ISDN connectivity.
Support for low-speed asynch-/synchronous serial lines is provided by the 2520/2521 platforms pictured in Figure 2.66. There are two low-speed connections with asynchronous data rates up to 115.2 Kbps and synchronous data rates up to 128 Kbps. Additionally, the LAN ports for Ethernet and Token-ring are also provided with an RJ-45 connection interface. Only one LAN interface is allowed to be configured and operative at any one time.
The 2520/2521 also provides a single ISDN BRI port. The 2520 Ethernet AUI or 10BaseT RJ-45/UTP adapter supports 10 Mbps and the 2521 token-ring DB-9 or RJ-45/UTP adapter supports 4 or 16 Mbps data rates.
The last two models, pictured in Figure 2.67, in the single LAN category of the 2500 series routers provides for up to eight low-speed asynch-/synchronous and two high-speed communications interfaces, a single ISDN BRI and a single LAN interface. The 2522 provides for Ethernet at 10 Mbps using an AUI or a 10BaseT RJ-45 connection. The 2523 model supports the 4 or 16 Mbps token-ring speeds using either the DB-9 or RJ-45 UTP ports.
Mission specific entry level routers in the 2500 series come in twelve unique offerings. The mission specific router models are configured with less memory than the single LAN models and execute IOS software images specifically designed for the CFRAD (CF), LAN FRAD (LF) and ISDN requirements. The special IOS images disable/enable unused ports through software. These mission specific routers give the single LAN router platforms the ability to act as frame relay access devices for connecting the location to frame relay networks without having to connect through a separate frame relay access piece of equipment. The CF models allow the router to also act as a frame relay switch for delivering information through frame relay networks. These models are however upgradeable to full functionality through full function IOS software and added memory.
The mission-specific routers are the exact models of the single LAN routers however, through the software have limited functionality. The 2501CF/2502CF routers have their respective LAN ports disabled by the IOS software and only allows configuration of the two high speed serial interfaces. The 2501LF/2502LF have their LAN ports enabled along with the ability to send LAN traffic through frame relay networks directly.
The 2503I/2504I provide for Ethernet and Token-Ring LAN connectivity respectively through ISDN BRI connections. The high speed serial connections available on the router are software disabled.
The 2520CF, 2521CF, 2522CF and 2523CF routers all have their ISDN BRI ports disabled and their respective LAN interfaces also disabled. The low- and high-speed ports are enabled and functional.
The 2520LF, 2521LF, 2522LF and 2523LF have all their LAN and WAN ports enabled however their ISDN BRI ports are disabled by the software.
For locations where a single device to support both routing and LAN connectivity for workgroups and small offices the Cisco 2500 series router/hub combinations is available in six different formats. Each format supports only one LAN segment but has multiple ports available for connecting workstations or servers. The integrated hubs on these router platforms save the small business or small office equipment and software costs while providing a full LAN/WAN solution.
The 2505, 2507, 2516 and 2518 router/hub offerings, diagrammed in Figures 2.68 and 2.69, provide a single segment Ethernet LAN environment.
Caption; The 2505/2507 models of the Cisco 2500 series router.
The 2505 supports up to eight Ethernet connections, the 2507 supports sixteen, the 2516 supports fourteen and the 2518 supports twenty-three Ethernet LAN connections to the hub. The router card of the 2518 connects to port 24 of the Ethernet hub allowing the 2518 to route LAN traffic over the WAN. The AUI port on the 2518 allows the 2518 to connect to an external Ethernet hub expanding the reach of the LAN segment. Both the 2516 and the 2518 have the ability to expand to five hubs using Lanoptics hub expansion units. Each platform has two high-speed serial interfaces. Only the 2505/2507 do not provide for an ISDN BRI interfaces.
The 2517 and 2519 support toke-ring LAN segments. The 2517 model allows for eleven token-ring LAN connections to the hub while the 2519 supports up to twenty-three token-ring LAN segments to the hub. The hub interfaces can either be 4 or 16 Mbps but all the ports must be using the same data rate. The 2519 contains a token-ring ring-in/ring-out ports for cascading token-ring hub equipment thereby increasing the size of the token-ring segment. Additionally, the ring ports 1-12 may be defined as a separate token-ring segment from ports 13-24. Both the 2517 and 2519 have router cards with token-ring RJ-45 connectors. The router cards attach to port 12 of the 2517 and port 24 of the 2519 routers. This enables the routers to transport LAN traffic over a WAN. The 2517 allows a single port on the 11 available ports to connect to another hub using an RJ-45 cross-over cable expanding the token-ring segment. On the 2519 the ring-in/ring-out ports allow for the expansion of the segment. An expansion unit is found on the top of the 2517 and 2519 to expand the hub to five hubs using Lanoptics supplied hubs. Both of these models have a single ISDN BRI port for switched backup use or bandwidth on demand use in conjunction with two high speed serial ports.
Small offices requiring more than one LAN are supported by the dual LAN router models. These are available in three different models. Figure 2.70 depicts the three dual LAN routers. All three models do not have ISDN BRI ports available. The 2513 supports one Ethernet 10 Mbps LAN segment and one toke-ring 4 or 16 Mbps LAN segments with two high-speed serial interfaces. The 2514 supports two Ethernet 10 Mbps LAN segments using AUI ports and the 2515 supports two Token-ring LAN segments at 4 or 16 Mbps using DB-9 connectors.
The modular routers in the 2500 series give the network engineer the ability to change and adapt the 2500 series routers unlike the previous models mentioned. There are two types of modular 2500 series routers. The two modular router models shown in Figure 2.71 differentiate themselves by the LAN support
. The 2524 connects Ethernet LANs while the 2525 provides Token Ring connections. Both allow up to three WAN modules configuring up to two synchronous serrial and one ISDN. The modules are available in the following configurations:
The three available slots shown in Figure 2.71 on the 2524 and 2525 are used for the WAN interfaces. The WAN slot on the right of the unit is keyed to allow only the ISDN BRI interface cards be installed. Likewise, the ISDN BRI cannot be installed in the first two WAN slots starting on the left of the router. The 2-wire, Switched 56 Kbps DSU/CSU WAN module allows for 56 Kbps dial up connections through the plain old telephone service (POTS) using an RJ-11 connection. The module connects directly form the RJ-11 port on the module to the RJ-11 port on the wall for connecting to the public telephone network.
The 4-wire 56/64 Kbps DSU/CSU WAN Module, Figure 2.71, for the 2524 and 2525 router provides dedicated leased line synchronous serial connections up to 64 Kbps using and RJ-48S connector directly to the wall plate connecting the line to the communications network.
The fractional T1/T1 DSU/CSU WAN module, shown in Figure 2.71, uses an RJ-48C connector to the network. This module supporting a 1.544 Mbps line provides either Nx56 or Nx64 channels up to a total of 24 individual channels at each speed. Each channel is defined as if it were its own unique interface.
The ISDN modules pictured in Figure 2.72 provide ISDN BRI connectivity using RJ-45 S/T connections. The ISDN BRI supports two B channels and one D channel. The two B channels together allow for a switched connection of 128 Kbps. The ISDN BRI module contains its own Terminal adapter and must be connected to an external NT1 device. The second ISDN BRI module has an integrated NT1 device and connects directly to the ISDN BRI port installed by the network provider.
The five in one synchronous serial WAN module shown in Figure 2.73 enables the one interface to support the following electrical interface standards using the appropriate cables:
The router side of the cable used has a DB-60 connector. The opposite end is headed with the appropriate interface required as specified by the line connection requirements.
All the 2500 series router platforms use the Motorola 20 MHz 68030 processor. Each system comes with a minimum of 8 MB of flash memory. The minimum system memory provided with the routers is 4 MB of DRAM partitioned between shared and primary DRAM memory. The total amount of DRAM available on the 2500 series graduates from 4 to 8 to 16 MB. All configurations of DRAM are partitioned into 2 MB of shared memory. The remaining DRAM is used for primary DRAM resulting in 2, 6 and 14 MB of primary DRAM respectively. For completeness consult Appendix G on 2500 series router memory requirements and IOS software feature support.
The Cisco 700M family is an ISDN multiprotocol access router. The 700M family supports ISDN basic rate interface (BRI) of 56, 64 or 128 Kbps remote access connections. The Cisco 700M family of access routers comes in two series: the 760 and 770. The 760 series has one Ethernet 10Mbps LAN interface and an ISDN BRI port. The 770 series includes a built in 4-port 10 Mbps Ethernet hub, ISDN BRI along with a call connect/disconnect switch on the format of the router to allow the user to manually connect or disconnect the ISDN BRI data linen connection.
The 760/770 series is broken further down into four models. Their features and functions are:
Shown in Figure 2.78, these models require an external Network Termination 1 (NT1) device for connectivity. It is based on the Intel 25 MHz 386 processor and comes with 1.5MB expandable to 2 MB over DRAM. The on-board NVRAM is 16 KB with a 1 MB flash memory. It can support up ton 1500 users and is available worldwide.
Shown in Figure 2.79, these models include an internal Network Termination 1 (NT1) device for connectivity. Additionally, these models have a second BRI port for external ISDN device connectivity or a second ISDN BRI line. It is based on the Intel 25 MHz 386 processor and comes with 1.5MB expandable to 2 MB over DRAM. The on-board NVRAM is 16 KB with a 1 MB flash memory. It can support up ton 1500 users and is available in North America only.
Shown in Figure 2.80, these models require an external Network Termination 1 (NT1) device for connectivity. It also includes two analog POTS RJ-11 ports for attaching phones, fax machines and modems to share the ISDN BRI simultaneously with data. This model also supports provider supplemental services over ISDN such as: call waiting, cancel call-waiting, call retrieve, call hold, 3-way call conferencing, and call transfer. It is based on the Intel 386 processor and comes with 1.5MB expandable to 2 MB over DRAM. The on-board NVRAM is 16 KB with a 1 MB flash memory. It can support up to 1500 users and is available worldwide.
Shown in Figure 2.81, these models include an internal Network Termination 1 (NT1) device for connectivity. Additionally, these models have a second BRI port for external ISDN device connectivity or a second ISDN BRI line. It also includes two analog POTS RJ-11 ports for attaching phones, fax machines and modems to share the ISDN BRI simultaneously with data. This model also supports provider supplemental services over ISDN such as: call waiting, cancel call-waiting, call retrieve, call hold, 3-way call conferencing, and call transfer. It is based on the Intel 386 processor and comes with 1.5MB expandable to 2 MB over DRAM. The on-board NVRAM is 16 KB with a 1 MB flash memory. It can support up ton 1500 users and is available North America only.
The 700M family can act as the DHCP server for the LAN attached devices assigning the remote locations IP addresses to the attached workstations. The 700M family can also have its IP or IPX addresses assigned from the provider or central site network connection using Multilink Point-to-Point Protocol (MPPP). The ISDN BRI connection can dial-on demand dynamically when it senses "interesting" traffic as defined by the remote location network administrator. This feature is useful when one ISDN BRI B channel connects to one location and traffic is generated for a second location. The second B channel can be activated for the life of the interesting traffic and then terminated. Also useful is setting FTP traffic as interesting to the router when transferring large file to another location by bringing up the second B channel to increase bandwidth.
In typical configurations there are many LAN workstation requiring access to another remote location. In many instances the 700M is used as a connection to the Internet. Internet service providers (ISPs) typically provide only one Internet address for the location. The 700M uses a many-into-one feature called Port and Address Translation (PAT) to over come this single address restriction. PAT is also used as a firewall function allowing to protect unknown resources from accessing the remote locaiton and privileging internal devices to access the Internet. The access can include web browsing, e-mail or file transfer to devices on the remote LAN network.
As described the 700M family is an access router. It's typical use is for occasional connectivity requirements from a remote location to another location. The location may be another remote office, the Internet or a central office location.