Caveats in Cisco IOS XE 3.6S Releases
Caveats describe unexpected behavior. Severity 1 caveats are the most serious caveats. Severity 2 caveats are less serious. Severity 3 caveats are moderate caveats and only select severity 3 caveats are included in this chapter.
This section describes caveats in Cisco IOS XE 3.6S releases. The following information is provided for each caveat:
- Symptom—A description of what is observed when the caveat occurs.
- Conditions—The conditions under which the caveat has been known to occur.
- Workaround—Solutions, if available, to counteract the caveat.
Note If you have an account on Cisco.com, you can also use the Bug Toolkit to find select caveats of any severity. To reach the Bug Toolkit, log in to Cisco.com and go to http://www.cisco.com/pcgi-bin/Support/Bugtool/launch_bugtool.pl. (If the defect that you have requested cannot be displayed, this may be due to one or more of the following reasons: the defect number does not exist, the defect does not have a customer-visible description yet, or the defect has been marked Cisco Confidential.)
The Dictionary of Internetworking Terms and Acronyms contains definitions of acronyms that are not defined in this document:
http://docwiki.cisco.com/wiki/Category:Internetworking_Terms_and_Acronyms_(ITA)
The following sections describe the open and resolved caveats in 3.6S Releases:
Open Caveats—Cisco IOS XE Release 3.6(2)S
This section documents the unexpected behavior that might be seen with the Cisco ASR 903 Router in Cisco IOS XE Release 3.6(2)S.
Symptoms: The router stops passing traffic on EVC interfaces.
Conditions: Occurs when you issue the default interface command and immediately restore the configuration. The issue occurs with configurations containing either a large number of EFPs or features that impact EFP programming at a lesser scale, such as QoS.
Workaround: Wait for the router to clear the old EFP configuration before adding a new configuration.
Symptoms: The router does not pass traffic towards the access side on virtual circuits (VCs) configured with QoS shaping output policy.
Conditions: Occurs when shaping is configured on class-default
Workaround: Configure shaping on user defined class
Symptoms: The router displays packet drops on some VPLS pseudowire virtual circuits (VCs) on the disposition side.
Conditions: Occurs under the following conditions: -The core network is running MPLS-TP tunnels -There is an SSO switchover on the remote end or an LDP neighbor reset on the peer end.
Workaround: There is no workaround.
Symptoms: The router stops passing VPLS unicast traffic.
Conditions: Occurs after you reload the router while it is passing VPLS unicast traffic.
Workaround: Perform one of the following actions:
– Clear the mac-address table on the affected virtual circuit (VC)
– Stop VPLS traffic until the MAC address table is cleared, then resume VPLS traffic.
Symptoms: The router may crash or restart; the console displays a SW_WDOG: expired message.
Conditions: Occurs under the following conditions:
– The router is configured with 63 or more instances of a unique EVC configured with a unique bridge domain interface (BDI).
– The router is sending IGMP joins to one multicast group.
– You perform a shutdown/no shutdown on the interface sending IGMP join messages.
– You perform an OIR on the router.
Workaround: There is no workaround.
Symptoms: Port shaper rate changes do not take effect.
Conditions: Occurs when QoS policies attached to EVCs on an interface do not include a shaper configuration; the issue does not occur on EFP policies that include a shaper in a class.
Workaround: Include a shaper in one class of the EFP policy.
Symptoms: The router applies the class-default QoS policy to all outgoing traffic.
Conditions: Occurs under the following conditions: -You configure multiple egress QoS policies on a Gigabit Ethernet interface. -You configure a multilink interface with no ingress QoS policy
Workaround: There is no workaround.
Symptoms: The router performs an RSP switchover instead of a thermal shutdown.
Conditions: Occurs when the facility-alarm critical exceed-action shutdown command is in the running configuration and some sensors go into a critical condition as indicated by the show environment all or show facility-alarm status commands.
Workaround: There is no workaround.
Symptoms: The convergence time for IS-IS IPv4 Loop Free Alternate Fast Reroute (LFA FRR) is greater than 50 milliseconds.
Conditions: Occurs when IS-IS LFA FRR reconverges following an interface shutdown while maintaining a large number of routes.
Workaround: There is no workaround.
Symptoms: The router stops passing traffic on a bridge-domain interface (BDI).
Conditions: Occurs when you apply the ip mtu command to a BDI interface for the first time.
Workaround: Remove and re-apply the ip mtu command.
Symptoms: The router does not increment QoS port shaper policy counters displayed by the show policy interface command.
Conditions: Occurs when you configure
– A class-default policy on a physical interface
– A class-based policy on an EVC interface
Workaround: There is no workaround; however, the router applies the QoS policy normally.
Symptoms: The router drops SAToP pseudowire traffic for 10 seconds following a core link failure.
Conditions: Occurs when the TDM controller generates an AIS and LOF alarm following a core link failure; the router drops traffic for 10 seconds after generating the alarm.
Workaround: There is no workaround.
Symptoms: A virtual circuit (VC) with an xconnect configuration stops forwarding traffic.
Conditions: Occurs with the 3.6(1) software under the following conditions:
– You add and remove EFPs on an interface.
– You remove and restore an interface configuration.
– You are using multiple VTY sessions simultaneously to configure the router.
Workaround: Reload the router; you can use either of the following methods to avoid this issue:
– Use a single VTY session for configuration.
– Apply the configuration mode exclusive command to prevent multiple VTYs from entering configuration mode at once.
Symptoms: The router displays interface module (IM) traceback errors.
Conditions: Occurs with the GLC-SX-MMD or GLC-LH-SMD (Catskills) SFPs under the following scenarios:
– IM reload
– SSO
– Router reload
– SFP insertion
Workaround: There is no workaround.
Resolved Caveats—Cisco IOS XE Release 3.6(2)S
This section documents the issues that have been resolved in Cisco IOS XE Release 3.6(2)S.
Symptoms: The standby RSP crashes during bootup.
Conditions: The issue can occur during bootup of a dual RSP system.
Workaround: There is no workaround.
Symptoms: The router displays intermittent traceback errors.
Conditions: Occurs when you configure REP.
Workaround: There is no workaround.
Symptoms: The router displays the following console message: Transceiver initialization failed: Unable to display idprom.
Conditions: The issue can occur when you perform an online insertion and removal (OIR) of an OC-3 interface module.
Workaround: Perform a hard OIR (IM replacement) followed by a soft OIR (RSP switchover) on the router.
Symptoms: BFD sessions flap on the router.
Conditions: Occurs when the router is running IP BFD sessions in echo mode with 64 200ms X3 timers.
Workaround: There is no workaround.
Symptoms: The router does not update IMA interface counters.
Conditions: Occurs after you perform an SSO on the router.
Workaround: There is no workaround.
Symptoms: A REP topology may reconverge during an RSP switchover. The consoles displays REP no-neighbor messages.
Conditions: Occurs when you configure REP between two Cisco ASR 903 Routers and you perform an RSP switchover.
Workaround: There is no workaround.
Symptoms: The port shaper rate changes on RSP switchover.
Conditions: Occurs under the following conditions: -You attach a shaper policy to an interface -The interface is configured with multiple EVCs -The EVC has a QoS policy attached.
Workaround: Remove and re-attach the policy on the interface.
Symptoms: CFM traceroute fails between two CE devices.
Conditions: Occurs under the following conditions:
– There is a CFM xconnect between higher-level MEPs
– The MEPs are between CE devices
– The CE devices are in a different domain.
Workaround: Disable CFM on the Cisco ASR 903 Router acting as a PE device.
Symptoms: The standby RSP crashes during ISSU.
Conditions: Occurs when you perform an ISSU downgrade from Release 3.6 to 3.5.
Workaround: There is no workaround.
Symptoms: REP flaps intermittently.
Conditions: Occurs with a hybrid REP configuration containing ports with and without Fast LSL enabled.
Workaround: Configure all interfaces with Fast LSL.
Symptoms: The router drops MPLS packets with a checksum of 0xFFFF.
Conditions: Occurs when the ASR 903 is acting as a label disposition edge label switch router (LSR).
Workaround: There is no workaround.
Symptoms: The ASR 903 does not establish BFD neighbors over port-channel 16.
Conditions: Occurs when you configure BFD on port-channel 16 between two ASR 903 routers.
Workaround: Configure BFD on port-channels 1 - 15.
Symptoms: The router drops traffic over a port-channel.
Conditions: Occurs when you perform the following sequence of events:
– Configure and bundle a Gigabit Ethernet interface into a port-channel
– Remove the interface from the port-channel
– Bundle another interface into the port-channel
Workaround: Reload the router.
Open Caveats—Cisco IOS XE Release 3.6(1)S
This section documents the unexpected behavior that might be seen with the Cisco ASR 903 Router in Cisco IOS XE Release 3.6(1)S.
Symptoms: The router stops passing traffic on EVC interfaces.
Conditions: Occurs when you issue the default interface command and immediately restore the configuration. The issue occurs with configurations containing either a large number of EFPs or features that impact EFP programming at a lesser scale, such as QoS.
Workaround: Wait for the router to clear the old EFP configuration before adding a new configuration.
Symptoms: The standby RSP crashes during bootup.
Conditions: The issue can occur during bootup of a dual RSP system.
Workaround: There is no workaround.
Symptoms: The router displays intermittent traceback errors.
Conditions: Occurs when you configure REP.
Workaround: There is no workaround.
Symptoms: BFD sessions flap on the router.
Conditions: Occurs when the router is running IP BFD sessions in echo mode with 64 200ms X3 timers.
Workaround: There is no workaround.
Symptoms: Port shaper rate changes do not take effect.
Conditions: Occurs when QoS policies attached to EVCs on an interface do not include a shaper configuration; the issue does not occur on EFP policies that include a shaper in a class.
Workaround: Include a shaper in one class of the EFP policy.
Symptoms: A REP topology may reconverge during an RSP switchover. The consoles displays REP no-neighbor messages.
Conditions: Occurs when you configure REP between two Cisco ASR 903 Routers and you perform an RSP switchover.
Workaround: There is no workaround.
Symptoms: The port shaper rate changes on RSP switchover.
Conditions: Occurs under the following conditions:
– You attach a shaper policy to an interface
– The interface is configured with multiple EVCs
– The EVC has a QoS policy attached.
Workaround: Remove and re-attach the policy on the interface.
Symptoms: The standby RSP crashes during ISSU.
Conditions: Occurs when you perform an ISSU downgrade from Release 3.6 to 3.5.
Workaround: There is no workaround.
Symptoms: The router cannot establish a PTP session when configured as a PTP slave device.
Conditions: Occurs when the router receives PTP packets containing a VPN or VRF label.
Workaround: There is no workaround.
Symptoms: The router applies the class-default QoS policy to all outgoing traffic.
Conditions: Occurs under the following conditions: -You configure multiple egress QoS policies on a Gigabit Ethernet interface. -You configure a multilink interface with no ingress QoS policy
Workaround: There is no workaround.
Symptoms: REP flaps intermittently.
Conditions: Occurs with a hybrid REP configuration containing ports with and without Fast LSL enabled.
Workaround: Configure all interfaces with Fast LSL.
Symptoms: The router drops MPLS packets with a checksum of 0xFFFF.
Conditions: Occurs when the ASR 903 is acting as a label disposition edge label switch router (LSR).
Workaround: There is no workaround.
Symptoms: The ASR 903 does not establish BFD neighbors over port-channel 16.
Conditions: Occurs when you configure BFD on port-channel 16 between two ASR 903 routers.
Workaround: Configure BFD on port-channels 1 - 15.
Symptoms: The router does not pass traffic over an EVC PC port-channel.
Conditions: Occurs when you perform the following sequence of actions: -Remove an EVC member link from a port-channel interface -Configure a trunk EFP -Set the interface to default -Add the EVC member link back into the port-channel interface
Workaround: Reload the router.
Symptoms: The router displays error messages similar to the following: %EVENTLIB-3-CPUHOG: SIP0: nile_mgr:
Conditions: Occurs when you boot the router running QoS configurations at a high scale, particularly queues.
Workaround: There is no workaround.
Resolved Caveats—Cisco IOS XE Release 3.6(1)S
This section documents the issues that have been resolved in Cisco IOS XE Release 3.6S(1).
Symptoms: Sweep ping fails when an ATM interface is configured with AAL5 encapsulation.
Conditions: Occurs when the ATM packet size is greater than 1484 bytes.
Workaround: There is no workaround.
Symptoms: The router displays traceback messages, after which interfaces stop passing traffic.
Conditions: The issue can occur when you reload the router
Workaround: There is no workaround.
Symptoms: QoS classification does not match traffic against an egress policy map between MPLS and IP access.
Conditions: This symptom is observed when a QoS policy is applied on an EVC bridge domain interface.
Workaround: Use one of the following workarounds:
– Reload the router.
– Remove and re-apply an encapsulation configuration such a VLAN.
– Remove and re-attach the bridge domain under the EVC.
– Perform a shutdown/no shutdown on the BDI interface.
Symptoms: The ASR 903 router forwards packets while in HSRP standby mode.
Conditions: Occurs when the ASR 903 is running HSRP and the HSRP session flaps.
Workaround: There is no workaround.
Symptoms: The ASR 903 router does not support LDP label packets when transmitted in PTP delay-request messages.
Conditions: Occurs when you configure the ASR 903 router as a PTP (1588 version) boundary clock and the router sends an MPLS label packet within delay-request traffic.
Workaround: Align the grandmaster clock source to the same IGP domain and use a prefix-list for local label filtering.
Symptoms: The interface manager crashes when you remove a BFD template.
Conditions: Occurs when you remove a BFD template or modify an MPLS-TP label.
Workaround: There is no workaround.
Symptoms: The router displays the following message when executing a Stateful Switchover (SSO): %TRANSCEIVER-3-CHECKSUM_ERROR
Conditions: Occurs intermittently when the router is in SSO mode and performing a switchover between RSPs. The console displays this message repeatedly on the new active RSP.
Workaround: There is no workaround.
Symptoms: The IOS kernel crashes.
Conditions: Occurs following a reload on a dual RSP system.
Workaround: Power cycle the router.
Symptoms: The router crashes.
Conditions: The issue can occur when you shut down and reenable an interface module.
Workaround: There is no workaround.
Symptoms: The router drops traffic passing across ATM MPLS layer 2 virtual circuits (VCs).
Conditions: Occurs when you increase the scale above 100 VCs.
Workaround: There is no workaround.
Symptoms: The router experiences line protocol flapping on serial interfaces.
Conditions: Occurs with the A900-IMA4OS and A900-IMA16D interface modules when the router is passing high volumes of HDLC or PPP traffic.
Workaround: Configure the no keepalive command on serial interfaces.
Symptoms: The router does not use a standby BITS clock source even when show commands indicate that the router has selected this clock source.
Conditions: Occurs when you configure a standby BITS clock source as an input clock source.
Workaround: There is no workaround.
Symptoms: The ASR 903 may reload with when acting as a hybrid clock.
Conditions: Occurs under the following conditions:
– The PLL mode is TOP CLIENT
– The session is in ACQUIRING state
– You issue the no ptp clock or domain 0 hybrid command.
Workaround: There is no workaround; however the issue occurs rarely.
Symptoms: Some members in an IMA group do not become active even though the interface controllers are up.
Conditions: Occurs when you perform an OIR on a remote line card or when the standby RSP becomes the active RSP.
Workaround: There is no workaround.
Symptoms: The T1/E1 interface module changes to inserted state during an in-service software upgrade (ISSU), causing the interface to fail and the router to generate a core file.
Conditions: Occurs when you perform an in-service software upgrade (ISSU) on a router with a T1/E1 interface module.
Workaround: Issue the shutdown command on the interface module before beginning ISSU; after ISSU is complete, issue the no shutdown command on the interface module.
Symptoms: On the Cisco ASR 903 router, the show environment command displays incorrect values, including P0 and P1 voltages and Amps values.
Conditions: This symptom is observed with the Cisco ASR 903 router when you apply the show environment command.
Workaround: There is no workaround.
Symptoms: The ASR 903 crashes and creates a core file.
Conditions: Occurs when the remote PE device is reloaded and an application such as VPLS or EoMPLS is running over MPLS TE FRR.
Workaround: There is no workaround.
Symptoms: The Cisco ASR 903 Router displays a core dump file.
Conditions: Occurs when the remote PE device is reloaded while running VPLS-TP.
Workaround: There is no workaround.
Symptoms: Ping does not work properly when traversing a BDI interface.
Conditions: Occurs when you configure MPLS on a BDI interface and ping packets are encapsulated in an MPLS header.
Workaround: There is no workaround.
Symptoms: The router drops traffic following a reload.
Conditions: Occurs when you reload the router while running a VRF configuration.
Workaround: Remove the configuration, reload the router, and re-apply the configuration.
Symptoms: Some CEM groups do not function correctly.
Conditions: Occurs when you configure more than 336 CEM groups on the T1/E1 or OC-3 interface module.
Workaround: There is no workaround; avoid configuring more than 336 CEM groups.
Symptoms: The router loses ARP table entries after a network link flaps.
Conditions: Occurs following a network link flap when the routers ARP table contains entries for next-hop neighbors connected over a router bridge domain interface.
Workaround: There is no workaround.
Symptoms: Egress QoS policies do not take effect on an EFP interface.
Conditions: Occurs when you apply an egress QoS policy to an interface configured with more than 37 EFPs.
Workaround: There is no workaround.
Symptoms: The router drops traffic for approximately 9 milliseconds.
Conditions: Occurs on the active RSP following an HA switchover.
Workaround: There is no workaround.
Symptoms: The router does not permit you to add an EFP interface to a split horizon group.
Conditions: Occurs after you make the following configuration changes:
– Configure 32 EFPs without a split horizon option to a bridge-domain interface.
– Configure 2 VPLS pseudowires.
Workaround: Configure 30 EFPs without a split horizon option, then apply the VPLS pseudowire configuration. After applying the VPLS pseudowire configuration, you can add 32 EFPs to the split horizon group.
Symptoms: Layer 4 port range security ACLs do not function properly.
Conditions: Occurs when you apply port range security ACLs to an EVC interface.
Workaround: There is no workaround.
Symptoms: The router does not complete a MAC address flush on the receiving side of a VPLS pseudowire.
Conditions: Occurs when the router receives a layer 2 MAC withdrawal over a VPLS pseudowire.
Workaround: There is no workaround.
Symptoms: The router does not classify traffic when using QoS ACLs.
Conditions: Occurs when you apply a QoS ACL using the range, lt, and gt operators.
Workaround: There is no workaround.
Symptoms: The router displays CPU hog messages or crashes.
Conditions: Occurs under conditions in which the router or an interface module is not responding and the interface module is in an improper state.
Workaround: There is no workaround; however the issue occurs very rarely.
Symptoms: The router drops PTP packets.
Conditions: Occurs when PTP packets traverse a BDI with encapsulation configured.
Workaround: There is no workaround.
Symptoms: The router displays I2C error messages intermittently.
Conditions: Occurs when you insert a copper SFP in the SFP interface module.
Workaround: There is no workaround.
Symptoms: An interface module goes into Inserted state during ISSU.
Conditions: Occurs when you perform an ISSU upgrade or downgrade.
Workaround: There is no workaround.
Symptoms: The router does not recognize interface modules after they are reset during a software upgrade.
Conditions: Occurs during ISSU upgrade or downgrade.
Workaround: There is no workaround.
Open Caveats—Cisco IOS XE Release 3.6(0)S
This section documents the unexpected behavior that might be seen with the Cisco ASR 903 Router in Cisco IOS XE Release 3.6(0)S.
Symptoms: Ping fails.
Conditions: Occurs when you configure AMI line code on a T1 controller.
Workaround: There is no workaround.
Symptoms: Multicast (S,G) entry not established.
Conditions: Occurs when you configure OIF and IIF within BDI that are part of a trunk EFP.
Workaround: Configure normal EVCs instead of trunk EVCs.
Symptoms: The router stops passing traffic on EVC interfaces.
Conditions: Occurs when you issue the default interface command and immediately restore the configuration. The issue occurs with configurations containing either a large number of EFPs or features that impact EFP programming at a lesser scale, such as QoS.
Workaround: Wait for the router to clear the old EFP configuration before adding a new configuration.
Symptoms: 64 byte Line rate traffic not achieved.
Conditions: Occurs with more than 11 links in a MLP bundle with A900-IMA16D interface module and packet size 64 bytes.
Workaround: There is no workaround.
Symptoms: BGP dynamic neighbor structures at the hub are not cleaned up after the spokes go down. The output of the show ip bgp all sum command continues to display dynamic neighbors.
Conditions: This issue is observed when all the following conditions are met:
– The scale environment for dynamic neighbors contains several thousand peers.
– The peers are brought up and then removed before they can transition into the Established state.
Workaround: There is no workaround.
Symptoms: The router displays traceback messages, after which interfaces stop passing traffic.
Conditions: The issue can occur when you reload the router
Workaround: There is no workaround.
Symptoms: The router displays intermittent traceback errors.
Conditions: Occurs when you configure REP.
Workaround: There is no workaround.
Symptoms: QoS classification does not match traffic against an egress policy map between MPLS and IP access.
Conditions: Occurs when you apply a QoS policy on an EVC bridge domain interface.
Workaround: Use one of the following workarounds:
– Reload the router.
– Remove and re-apply an encapsulation configuration such a VLAN.
– Remove and re-attach the bridge domain under the EVC.
– Perform a shutdown / no shutdown on the BDI interface.
Symptoms: The router crashes.
Conditions: Occurs when you remove the fast-reroute remote-lfa level-2 mpls-ldp command from a configuration.
Workaround: This command is not currently supported; avoid including it in a configuration.
Symptoms: There is a delay in route processor synchronization after an SSO.
Conditions: This issue is observed when iBGP NSR is enabled and under scale conditions.
Workaround: There is no workaround.
Symptoms: Cannot configure policing and marking together in the same class of the egress policy-map.
Conditions: Set and police statements together in the same class of a policy is rejected at the CLI.
Workaround: In order to achieve marking and policing at the ingress we can use a conditional policer but this is not supported at the egress.
Symptoms: Type 1 MVPN routes are not created.
Conditions: This issue is observed when the IP address of a loopback interface is changed.
Workaround: Create a dummy neighbor under the address-family ipv4 mvpn configuration or the address-family ipv6 mvpn configuration. Alternatively, unconfigure and reconfigure the MDT group under the VRF configuration.
Symptoms: Standby gateway starts forwarding packet for some of the HSRP sessions.
Conditions: This is seen on flapping the HSRP session.
Workaround: There is no workaround.
Symptoms: ICMP unreachable messages are sent even though route for destination ip is present in routing table. There is no ACL applied on any of the interface.
Conditions: This is seen on reload with VRRP configuration present on incoming interfaces.
Workaround: There is no workaround.
Symptoms: The router displays an error message similar to the following: FMFP-3-OBJ_DWNLD_TO_CPP_FAILED: SIP0: fman_fp_image: frr 0x1029 download to CPP failed
Conditions: Occurs when you shut down a backup tunnel and shut down an FRR-protected interface, disabling TE tunnels.
Workaround: None; the error does not impact traffic forwarding.
Symptoms: ICMP unreachable messages are sent when a route for the destination ip address exists in the routing table. There is no ACL applied on any of the interface.
Conditions: Occurs under the following conditions:
– There is a VRRP configuration applied to incoming interfaces.
– There are not ACLs applied on any interface.
– Your reload the router.
Workaround: There is no workaround.
Symptoms: The router displays an error message similar to the following: FMFP-3-OBJ_DWNLD_TO_CPP_FAILED: SIP0: fman_fp_image: frr 0x1029 download to CPP failed
Conditions: Occurs when you shut down a backup tunnel interface and a FRR-protected interface, bringing down MPLS TE tunnels.
Workaround: There is no workaround; the error does not appear to impact traffic forwarding.
Symptoms: When the no authentication command is run on one BFD template, other MHOP BFD sessions on which authentication has been configured may change to the Down state.
Conditions: This issue is observed when there are multiple sessions that use different maps and templates.
Workaround: There is no workaround.
Symptoms: MPLS convergence time is higher than normal.
Conditions: Occurs when the router is processing more than 3107 iBGP and label prefixes.
Workaround: There is no workaround.
Symptoms: The interface manager crashes when you remove a BFD template.
Conditions: Occurs when you remove a BFD template or modify an MPLS-TP label.
Workaround: There is no workaround.
Symptoms: The router displays the following message when executing a Stateful Switchover (SSO): %TRANSCEIVER-3-CHECKSUM_ERROR
Conditions: Occurs intermittently when the router is in SSO mode and performing a switchover between RSPs. The console displays this message repeatedly on the new active RSP.
Workaround: There is no workaround.
Symptoms: An imposition failure occurs on VCs configured with MPLS TP LSPs.
Conditions : Occurs under the following conditions:
– There are input and output QoS policy-maps configured on service instance interfaces.
– The router is configured with 255 MPLS TP tunnels.
– The router is configured with a high number of virtual circuits (VCs).
– The RSP in slot 0 is acting as the active RSP.
– An event occurs that causes the router to tear down and rebuild all MPLS TP tunnels and VCs at once.
Workaround : Remove and reconfigure the service instance.
Symptoms: When L2VPN Pseudowire Stitching is configured between a static segment and a dynamic segment, both segments may move to the Down state.
Conditions: This issue is observed when L2VPN Pseudowire Stitching is configured between a static segment and a dynamic segment.
Workaround: There is no workaround.
Symptoms: The router displays the following console message: Transceiver initialization failed: Unable to display idprom
.
Conditions: The issue can occur when you perform an online insertion and removal (OIR) of an OC-3 interface module.
Workaround: Perform a hard OIR (IM replacement) followed by a soft OIR (RSP switchover) on the router.
Symptoms: The router does not pass IPv6 OSPF traffic.
Conditions: Occurs when the router passes traffic at the full line rate of a link.
Workaround: Reduce the traffic rate by 10%.
Symptoms: The IOS kernel crashes.
Conditions: Occurs following a reload on a dual RSP system.
Workaround: Power cycle the router.
Symptoms: A configuration with a high number of down MEPs does not function properly.
Conditions: Occurs when you configure 500 or more down MEPs with 500 or more xconnect configurations between service instances.
Workaround: Configure no more than 300 CFM sessions.
Symptoms: The router crashes.
Conditions : The issue can occur when you shut down and reenable an interface module.
Workaround : There is no workaround.
Symptoms: The router displays CPU utilization traceback messages and drops all multicast traffic for 20–50 seconds.
Conditions: Occurs under the following conditions:
– Multicast is enabled with more than 500 multicast groups
– The router is using RSP1B in SSM mode
– BDI is configured on the access side of the router
– There are 24 EFPs on each bridge domain
– You enter a shutdown command on the access interface.
Workaround: There is no workaround.
Symptoms: The router does not pass CFM traffic over an Ethernet CFM cross-connect.
Conditions: Occurs under the following conditions:
– There is a CFM xconnect between two Cisco ASR 903 Router devices
– You perform an OIR and set a default interface.
Workaround: Do not continuously perform an OIR and set a default interface.
Symptoms: The router experiences traffic loss for between 10 and 50 seconds during RSP switchover.
Conditions: Occurs when you perform an RSP switchover on a router with a ten gigabit Ethernet interface module.
Workaround: There is no workaround.
Symptoms: The router drops traffic passing across ATM MPLS layer 2 virtual circuits (VCs).
Conditions: Occurs when you increase the scale above 100 VCs.
Workaround: There is no workaround.
Symptoms: The line protocol repeatedly drops (flaps) on serial interfaces.
Conditions: Occurs when you configure HDLC or PPP on serial interfaces on the A900-IMA4OS or A900-IMA16D interface modules when the router is passing high traffic volumes.
Workaround: Configure the no keepalive command on serial interfaces.
Symptoms: The router cannot download the ACL database.
Conditions: Occurs when the router is configured with an ACL containing more than 400 access control entries (ACEs).
Workaround: There is no workaround.
Symptoms: Interface modules stop passing traffic during an RSP switchover.
Conditions: Occurs when the router switches over to the standby RSP while traffic is passing on interface modules.
Workaround: There is no workaround.
Symptoms: The router crashes during when SNMP uses a high percentage of CPU for an extended period.
Conditions: Occurs when SNMP is running the background with an average of 50% CPU utilization for more than 8 hours.
Workaround: Reduce the load on the CPU using SNMP poll and SNMP walk.
Symptoms: BFD sessions flap on the router.
Conditions: Occurs when the router is running IP BFD sessions in echo mode with 64 200ms X3 timers.
Workaround: There is no workaround.
Symptoms: The router crashes.
Conditions : Occurs when you apply traffic soaking to the router with L2VPN services configured.
Workaround : There is no workaround.
Symptoms: The router experiences packet drops when passing 64 byte packets.
Conditions: Occurs when the router is passing 64 byte packets at the line rate on the OC-3 interface module.
Workaround: Configure a larger packet size on the interface.
Symptoms: Some CEM groups do not function correctly.
Conditions : Occurs when you configure more than 196 CEM groups on the T1/E1 or OC-3 interface module.
Workaround : There is no workaround; avoid configuring more than 196 CEM groups.
Symptoms: The router stops passing VPLS unicast traffic.
Conditions: Occurs after you reload the router while it is passing VPLS unicast traffic.
Workaround: Perform one of the following actions:
– Clear the mac-address table on the affected virtual circuit (VC)
– Stop VPLS traffic until the MAC address table is cleared, then resume VPLS traffic.
Symptoms: Shutting down a static multisegment VFI causes traffic to flow in one direction.
Conditions: This issue is observed when you configure a point-to-point VFI with two static neighbors and then shut down the VFI by using the shutdown command.
Workaround: There is no workaround.
Symptoms: The router drops multicast packets on layer 3 interfaces.
Conditions: Occurs when you configure 63 bridge domains per port and the router sends IGMP joins from all of the bridge domains to the same IGMP group.
Workaround: You can apply the following workarounds:
– Applying a policy-map on each EVC can reduce the packet drops to some extent.
– Increase the default port queue size.
Symptoms: The router drops VPLS traffic on one or more virtual circuits (VCs).
Conditions: Occurs when you reload a CPE or UPE device when there approximately 100 VCs configured between the UPE and NPE devices.
Workaround: Issue the clear xconnect command on the affected VC.
Symptoms: Some members in an IMA group do not become active even though the interface controllers are up.
Conditions : Occurs when you perform an OIR on a remote line card or when the standby RSP becomes the active RSP.
Workaround : There is no workaround.
Symptoms: The OC-3 interface module crashes when you perform multiple RSP switchovers.
Conditions : Occurs when the router is running a CEM configuration configured at full scale on all ports and passing traffic.
Workaround : There is no workaround.
Symptoms: Serial interfaces configured with HDLC display false LOF or AIS alarms.
Conditions: Occurs when you configure a high volume of serial interfaces using HDLC.
Workaround: Remove and re-apply the serial interface configuration.
Symptoms: The T1/E1 interface module changes to inserted state during an in-service software upgrade (ISSU), causing the interface to fail and the router to generate a core file.
Conditions: Occurs when you perform an in-service software upgrade (ISSU) on a router with a T1/E1 interface module.
Workaround: Issue the shutdown command on the interface module before beginning ISSU; after ISSU is complete, issue the no shutdown command on the interface module.
Symptoms: CEM circuits become inactive.
Conditions: Occurs when you perform an OIR, reload, or when you reconfigure a CEM circuit on the router. The issue occurs more consistently when the router is running more than 300 CEM circuits.
Workaround: Issue the clear xconnect all command.
Symptoms: The router may crash or restart; the console displays a SW_WDOG: expired
message.
Conditions: Occurs under the following conditions:
– The router is configured with 63 or more instances of a unique EVC configured with a unique bridge domain interface (BDI).
– The router is sending IGMP joins to one multicast group.
– You perform a shutdown/no shutdown on the interface sending IGMP join messages.
– You perform an OIR on the router.
Workaround: There is no workaround.
Symptoms: The show environment command displays incorrect values, including P0 and P1 voltages, PSU status, PSU voltage, and critical alarms.
Conditions : Occurs when you apply the show environment command.
Workaround : There is no workaround.
Symptoms: The router crashes.
Conditions : Occurs under any of the following conditions:
– You perform an OIR on an interface module.
– You issue the no ppp multilink command on all MLP member links.
– You set the MTU to a higher value on an MLP bundle.
Workaround : There is no workaround.
Symptoms: The Cisco ASR 903 Router displays a core dump file.
Conditions: Occurs when the remote PE device is reloaded while running VPLS-TP.
Workaround: There is no workaround.
Symptoms: The router stops forwarding traffic across one or more EoMPLS virtual circuits (VC)s.
Conditions: Occurs when you perform a shut/no shutdown on the MPLS TE tunnel carrying the VC.
Workaround: Issue the clear xconnect command on the VC.
Symptoms: The router floods all EFPs in the sam e split horizon group with IGMP join messages.
Conditions: Occurs when the router is sending an IGMP join containing a dot1q tag for one EVC.
Workaround: None.
Symptoms: The router drops traffic following a reload.
Conditions : Occurs when you reload the router while running a VRF configuration.
Workaround : Remove the configuration, reload the router, and re-apply the configuration.
Symptoms: Some CEM groups do not function correctly.
Conditions : Occurs when you configure more than 196 CEM groups on the T1/E1 or OC-3 interface module.
Workaround : There is no workaround; avoid configuring more than 196 CEM groups.
Symptoms: An IPC Init failure occurs during downgrade, which makes the standby reload continuously.
Conditions : Occurs when you perform an ISSU downgrade from IOS XE 3.6 to IOS XE 3.5.1 or 3.5.
Workaround : There is no workaround.
Symptoms: The router experiences CPP download failures when sending IGMP join messages.
Conditions: Occurs when the router is configured with a trunk EFP in SM mode on the access side and is sending IGMP join messages to more than 1970 multicast groups.
Workaround: There is no workaround.
Symptoms: The router drops traffic on ATM subinterfaces using layer 2 PVCs.
Conditions: Occurs when you create 255 or more ATM PVCs.
Workaround: There is no workaround.
Symptoms: The router displays core dump files.
Conditions: Occurs when you perform an RSP switchover when CEF routes are configured.
Workaround: There is no workaround.
Symptoms: The router sends traffic for virtual circuits (VCs) over Gigabit Ethernet interfaces instead of MPLS-TP tunnels.
Conditions: Occurs when you perform an interface module OIR and the VCs are configured with a preferred path as the MPLS-TP tunnel.
Workaround: There is no workaround.
Symptoms : The router does not pass MLP traffic.
Conditions : Occurs when you perform an RSP switchover with an existing MLP configuration.
Workaround : There is no workaround.
Symptoms: A REP topology may reconverge during an RSP switchover. The consoles displays REP no-neighbor messages.
Conditions : Occurs when you configure REP between two Cisco ASR 903 Routers and you perform an RSP switchover.
Workaround : There is no workaround.
Symptoms: CFM traceroute fails between two CE devices.
Conditions: Occurs under the following conditions:
– There is a CFM xconnect between higher-level MEPs
– The MEPs are between CE devices
– The CE devices are in a different domain.
Workaround: Disable CFM on the Cisco ASR 903 Router acting as a PE device.
Symptoms: Multicast replication does not occur on all BDI interfaces on a given trunk EFP.
Conditions: Occurs under the following conditions:
– The router is configured with 63 or more BDIs
– The BDIs are configured as OIFs on a trunk EFP.
– The port on which the EFP is configured is in a multicast group.
Workaround: There is no workaround.
Symptoms: The router displays an Eamapper error.
Conditions: Occurs under the following conditions:
– The router is configured with a port channel interface with 2 member links.
– The port channel
– The configuration contains 48 EFPs with 24 EFPs in a given bridge domain
– SSM is enabled on the local and a remote router
– The router sends an IGMP join to a single multicast group.
Workaround: There is no workaround.
Symptoms: The router experiences a drop in forwarded packets on an MLPPP bundle.
Conditions: Occurs when the bundle is using 64% or more of the available bandwidth and an MTU value is configured on the bundle.
Workaround: There is no workaround.
Symptoms: The router crashes and reboots.
Conditions: Occurs when you perform a longevity test with traffic soaking while using Ethernet features such as EoMPLS, VPLS, CFM, or Y1731.
Workaround: There is no workaround.
Symptoms: The router loses ARP table entries after a network link flaps.
Conditions: Occurs following a network link flap when the router’s ARP table contains entries for next-hop neighbors connected over a router bridge domain interface.
Workaround: There is no workaround.
Symptoms: Egress QoS policies do not take effect on an EFP interface.
Conditions: Occurs when you apply an egress QoS policy to an interface configured with more than 37 EFPs.
Workaround: There is no workaround.
Symptoms: The router displays an EgBridgeError_0 error when sending multicast traffic.
Conditions: Occurs in the following conditions:
– There are 40 bridge domain interfaces (BDIs) sending IGMP joins to a single multicast group.
– There are more than 40 OIFs and 24 EVCs in each bridge domain.
Workaround: There is no workaround.
Symptoms: The router crashes during RSP switchover or bootup.
Conditions: Occurs when L2VPN services are passing bidirectional traffic on the router and you perform a reload or RSP switchover.
Workaround: There is no workaround.
Symptoms: The router crashes.
Conditions: Occurs during bootup when the router is running BFD and CFM sessions that are offloaded to hardware.
Workaround: There is no workaround.
Symptoms: L2 OIF replication does not take effect when you add or delete an EVC.
Conditions: Occurs after a bridge domain or split horizon group change.
Workaround: There is no workaround.
Resolved Caveats—Cisco IOS XE Release 3.6(0)S
This section documents the issues that have been resolved in Cisco IOS XE Release 3.6(0)S.
Symptoms: BFD flaps when you perform a RSP switchover.
Conditions: Occurs under the following conditions:
– The router is configured as a mid-point node.
– The router is running MPLS-TP sessions with BFD.
– You perform a soft OIR.
Workaround: None.
Symptoms: Interfaces go into a down-down state.
Conditions: The issue can occur when you use a script to implement a full-scale configuration.
Workaround: Perform an RSP switchover on both sides of the connection.
Symptoms: The RSP is unable to modify the configuration file or execute show interface commands.
Conditions: Occurs following an RSP switchover.
Workaround: None.
Symptoms: The router does not save the port-channel load-balance-hash-algo command in the running configuration.
Conditions: Occurs when you select the src-ip , dst-ip , or src-dst-ip hash algorithm.
Workaround: None.
Symptoms: Traffic switches over the protect-lsp of a mpls-tp tunnel interface, even though corresponding working-lsp link is active.
Conditions: Occurs when the protect-lsp bfd goes down while the protect lsp out-link interface going down.
Workaround: None.
Symptoms: Policy-map counters do not function properly.
Conditions: Occurs when you configure an ACL-based class-map under a policy-map.
Workaround: None.