Specifications

Caveats for Cisco IOS Release 12.0

78-6455-12

Interfaces and Bridging

Workaround: Use DLSw with TCP encapsulation instead of FST encapsulation, or use a different

router platform.

Interfaces and Bridging

• CSCdm45164

Enabling Weighted Fair Queuing (WFQ) on an interface that belongs to a transparent bridging

bridge group may cause packets that are egressing that interface to be sent out of order. This

situation causes failure in terminated and bridged Logical Link Control 2 (LLC2) sessions.

Workaround: Disable WFQ with the no fair-queue interface configuration command.

• CSCds07197

On Cisco 2600, 3600, and 7200 series routers running Cisco IOS Release 12.1 and Release 12.1 T

the maximum configurable transmission unit size under the Token Ring interface is 4464 bytes.

There is no workaround.

• CSCds21753

A Cisco router with a FDDI may corrupt some packets that are switched out of the FDDI. This

problem has been confirmed only for the FDDI<->FDDI case with Multiprotocol Label Switching

(MPLS) enabled. This problem may also affect FDDI<->ATM with MPLS, but is not confirmed for

that case or any case other than FDDI<->FDDI with MPLS.

Workaround: Keep a continuous stream of pings running from the router that is reporting the cyclic

redundancy check (CRC) errors introducing the corruption targeted at the loopback address.

IP Routing Protocols

• CSCdr70471

Open Shortest Path First (OSPF) allocates and deallocates memory for a variety of needs. If the

problem persists, the system may end up with badly fragmented memory. The only solution at that

time would be to reboot the router.

Workaround: Reduce the number of link-state advertisements (LSA) in the OSPF database.

Alternate workaround: Design a stable network, minimizing LSA withdrawals and reissue (that is,

summarize routes into the core).

• CSCds23901

For a multicast source directly connected to a router, the “R” flag is set when a (S,G,R) prune

message is received if the (S,G) O-list is NULL 2. The prune message was received on the

non-incoming interface (NON-IIF). This situation causes the incoming interface (IIF) to change to

the Rendezvous Point (RP) and disconnects the IIF from the source. The “F” flag is reset. As a

result the RP loses the S and G states and new receivers can not join the multicast source.

Workaround: Configure the ip pim rp-proxy-join on the RP. This allows the RP’s S and G states

to join the first-hop router and have the O-list populated. Multicast traffic will continue to flow to

the RP but if the RP’s (S,G) O-list is NULL, it will fast-drop this traffic.