Cisco IOS Software Releases 11.3

Field Notice: Input Queue Wedged by IPX RIP Packets in Cisco IOS 11.3(4) and 11.3(4)T

August 11, 1998

Products Affected




This defect may affect any user running IPX routing.

Problem Description

If an IPX RIP request packet is not replied to by the router, it will stay in the input queue and not be released. Accumulated packets could cause the input queue to fill, causing severe problems for all protocols.

The RIP request will not be answered if:

  • the requested network is not in the table, and no default route exists.

  • the requested network is denied via an output filter.

  • the requested network is split-horizoned (that is, the network was learned on the same interface from which the request came).


This software defect is identified by bug ID CSCdk19752.

Note:?If you are a registered CCO user and you have logged in, you can view bug details.

View CSCdk19752 (registered customers only)

Problem Symptoms

If you are running any of the affected Cisco IOS releases and have IPX configured on an interface whose input queue fails to automatically clear, you may be experiencing this defect.

A sample configuration of the problem is shown below:

hostname test_router
ipx routing 00e0.1ee3.bc0b
interface Ethernet0
ip address
no ip directed-broadcast
ipx network 4343

Output of the show interface command is shown below:

test_router#show interface ethernet0
Ethernet0 is up, line protocol is up
Hardware is PQUICC Ethernet, address is 00e0.1ee3.bc0b (bia 00e0.1ee3.bc0b)
Internet address is
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, rely 128/255, load 1/255
Encapsulation ARPA, loopback not set
ARP type: ARPA, ARP Timeout 04:00:00
Last input 01:40:57, output 00:00:06, output hang never
Last clearing of "show interface" counters never
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 75/75, 0 drops
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
1063908 packets input, 114105706 bytes, 0 no buffer
Received 1054275 broadcasts, 0 runts, 0 giants, 24738 throttles
24711 input errors, 1 CRC, 0 frame, 0 overrun, 24710 ignored, 0 abort
0 input packets with dribble condition detected
35605 packets output, 3713659 bytes, 0 underruns
0 output errors, 7 collisions, 1 interface resets
0 babbles, 0 late collision, 27 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out


A temporary workaround is to:

  1. Clear the interface with the clear interface ethernet0 command.

  2. Reload router with the reload command.

Cisco recommends that customers running IPX routing with the affected software should upgrade to Cisco IOS interim release 11.3(4.4)/11.3(4.4)T or later. Interim releases must be obtained through Cisco's Technical Assistance Center (TAC).

As always, Cisco recommends that customers move to a maintenance release as soon as available. The next maintenance releases that contain this fix are 11.3(5) and 11.3(5)T. They will be available from CCO's Software Center after August 17, 1998.

For More Information

If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods: