For the purpose of both the CCNA and CCDA, you’ll also need to be familiar with routing IPX traffic across an internetwork. Recall from Chapter 7 that IPX functionality is enabled on a router through the use of the ipx routing command. After issuing this command, you can assign IPX addresses to interfaces by providing a network number, and optionally (on Ethernet, Token Ring, or FDDI interfaces) specifying an encapsulation type.
Setting up IPX routing is exceptionally simple. What I didn’t tell you in the last chapter is that after issuing the ipx routing command, your router is already running an IPX routing protocol – IPX RIP. Though much like the RIP protocol looked at previously, IPX RIP and IP RIP are not compatible – they are different routing protocols, even if they exhibit similar characteristics. For example, both define infinity as 16 hops, meaning that the maximum diameter of an IPX network running IPX RIP is 15 hops. IPX RIP update packets are broadcast every 60 seconds by default.
One major difference between the IP and IPX versions of RIP is the metric used. IPX RIP uses something referred to as a “tick” as its metric. A tick is the expected delay in reaching a network, and is defined as 1/18th of a second. In cases where the tick count between two networks is equal, hop count is used as the tiebreaker.
Figure: IPX network configuration.
For the purpose of illustrating IPX routing, we’re going to configure our routers as per the figure above. In this scenario we have two routers and three networks. The steps below outline the configuration of Router A.
RouterA#config t
Enter configuration commands, one per line. End with CNTL/Z.
RouterA(config)#ipx routing
RouterA(config)#int s0
RouterA(config-if)#ipx network 99
RouterA(config-if)#int e0
RouterA(config-if)#ipx network 102A
The configuration of Router B is similar:
RouterB#config t
Enter configuration commands, one per line. End with CNTL/Z.
RouterB(config)#ipx routing
RouterB(config)#int s0
RouterB(config-if)#ipx network 99
RouterB(config-if)#int e0
RouterB(config-if)#ipx network 101A
With only the few steps shown, we have enabled IPX on the routers, given the appropriate interfaces IPX addresses, and even enabled IPX RIP routing – recall that it is enabled automatically as part of the ipx routing command. The next step is taking a look at our IPX routing tables. This is done using the show ipx route command, which is shown on
Router A below.
RouterA#sh ipx route
Codes: C - Connected primary network, c - Connected secondary network
S - Static, F - Floating static, L - Local (internal), W - IPXWAN
R - RIP, E - EIGRP, N - NLSP, X - External, A - Aggregate
s - seconds, u - uses, U - Per-user static
3 Total IPX routes. Up to 1 parallel paths and 16 hops allowed.
No default route known.
C 99 (HDLC), Se0
C 102A (NOVELL-ETHER), Et0
R 101A [07/01] via 99.0060.5cc4.f41b, 13s, Se0
Notice that an IPX routing table has a slightly different format, but still displays similar information to an IP routing table. It shows that networks 99 and 102A are directly connected, and also shows a route to network 101A via IPX address 99.0060.5cc4.f41b, which is the S0 interface on Router B. To check and see whether Router A can route all the way to network 101A properly, we can use an IPX ping, specifying the IPX address of interface E0 on Router B.
Router#ping ipx 101a.0060.5cc4.f88b
Type escape sequence to abort.
Sending 5, 100-byte IPXcisco Echoes to 101a.0060.5cc4.f88b, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 32/35/36 ms
Since our IPX ping worked, Router A and Router B are both configured with complete information about the IPX internetwork.
