If the fact that the ipx routing command enables IPX RIP routing wasn’t enough of a surprise for you, you should also know that it enables the propagation of Service Advertisement Protocol updates as well. If you recall from Chapter 4, SAP advertisements are sent out by Netware servers periodically to announce services that they have available. By default, these announcements are sent out every 60 seconds. But why do routers forward them? Well, since they’re broadcasts, SAP messages usually wouldn’t leave the broadcast domain, which means that client systems wouldn’t be able to find out about services offered by Netware servers on different networks.
On most networks running Netware, SAP isn’t nearly as important as it once was. For example, on networks that run NDS, clients usually query the NDS directory to find out about servers as necessary. However, with older versions of Netware, clients relied on SAP announcements to find file servers, print servers, and so forth. Whether you need SAP advertisements propagated through your network (or to what extent), will usually depend upon the version of Netware you are running.
When Cisco routers forward SAP broadcasts to another router, they are simply making that router aware of servers available on other networks – all for the benefit of clients. Clients will find out about the servers on other networks via the SAP broadcasts sent out every 60 seconds by the router. Consider the network shown in the figure above. In it, Server A is sending out SAP broadcasts that are ultimately forwarded to Router B. Router B makes clients on Network 101A aware of the fact that Server A exists and is offering file and services. The command to view the SAP table on a router is show ipx servers.
RouterB#show ipx servers
Codes: S - Static, P - Periodic, E - EIGRP, N - NLSP, H - Holddown, + = detail
1 Total IPX Servers
Table ordering is based on routing and server info
Type Name Net Address Port Route Hops Itf
P 4 ServerA FD819A6B.0000.0000.0001:0451 1/01 1 Et0
In SAP broadcasts, the services offered by servers are designated by hexadecimal identifiers – for example, the hex value of 4 represents a file server, while 7 represents a print server.
While the actual configuration of basic IPX routing is exceptionally simple, there are still a few commands that you’ll want to have in your back pocket for the purpose of understanding a little more about the routing table updates and IPX traffic on your network. The show ipx traffic command provides you with information on the IPX traffic that has been sent and received by a router. I’ve truncated the output to show only basic information provided by the command below.
RouterA#show ipx traffic
System Traffic for 0.0000.0000.0001 System-Name: RouterA
Rcvd: 996 total, 153 format errors, 0 checksum errors, 0 bad hop count,
932 packets pitched, 305 local destination, 0 multicast
Bcast: 301 received, 5367 sent
Sent: 5375 generated, 0 forwarded
0 encapsulation failed, 0 no route
SAP: 4 Total SAP requests, 0 Total SAP replies, 0 servers
4 SAP general requests, 0 ignored, 0 replies
0 SAP Get Nearest Server requests, 0 replies
0 SAP Nearest Name requests, 0 replies
0 SAP General Name requests, 0 replies
0 SAP advertisements received, 0 sent
0 SAP flash updates sent, 1 SAP format errors, last seen from 101A.00e0.
RIP: 5 RIP requests, 3 RIP replies, 2 routes
50 RIP advertisements received, 5354 sent
1 RIP flash updates sent, 0 RIP format errors
Like the commands used to view information on the status of IP RIP and IGRP, there are also debug commands to view IPX RIP and SAP status information. These commands include:
- Debug ipx routing activity. This command will show the full information on IPX RIP messages being broadcast from interfaces, including the routes contained in the update. The command debug ipx routing events shows only limited information, such as when an update has been sent or received.
- Debug ipx sap activity. This command displays detailed information of SAP broadcasts sent and received, including the server information they contain. Using the command debug ipx sap events provides only limited information on the actual updates.
To turn debugging off, you can use either the “no” version of these commands, or the undebug all command, which turns debugging off globally.
To view information on all the protocols that your router is currently routing, you can use the show protocols command. It will display not only whether routing for a protocol is enabled, but also the status and addresses of interfaces. The command provides a quick and effectively way of gathering important router status information in a single command.
Internet Protocol routing is enabled
IPX routing is enabled
Ethernet0 is up, line protocol is up
Internet address is 10.0.10.1/24
IPX address is 102A.00e0.f751.d6af
Serial0 is up, line protocol is up
Internet address is 10.0.20.1/24
IPX address is 99.00e0.f751.d6af