Table Of Contents
Release Notes for Cisco IOS Release 12.0(11)ST3
Determining the Software Version
New Features in Release 12.0(11)ST3
Diff-Serv-aware Traffic Engineering
Label Distribution Protocol MIB
New MPLS VPN Line Card for GSR
Restrictions in Release 12.0(11)ST3
MPLS Class of Service Restriction
Open Shortest Path First Restriction
PIRC and Access Lists Restriction
New Features in Release 12.0(10)ST
MPLS Traffic Engineering and Enhancements
MPLS Traffic Engineering Fast Reroute—Link Protection
MPLS Label Distribution Protocol
MPLS Egress NetFlow Accounting
ATM Adaptation Layer Type 5 Transport over MPLS
VRF-Specific Static ARP Entry Support
New MPLS VPN Line Card Support for GSR
VPN Slow-Path Support on Engine 2 at Deaggregation Point (Between PE-P)
New Features in Release 12.0(9)ST
MPLS Support on Dynamic Packet Transport
Open Caveats for Release 12.0(11)ST3
Resolved Caveats—Release 12.0(11)ST3
Cisco IOS Software Documentation Set
Release 12.0 Documentation Set
Obtaining Technical Assistance
Contacting TAC by Using the Cisco TAC Website
Release Notes for Cisco IOS Release 12.0(11)ST3
March 2, 2001
These release notes for the Cisco 7200 series, Cisco 7500 series, and Cisco 12000 series routers support Cisco IOS Release 12.0(11)ST3. These release notes are updated, as needed, to describe new features, memory requirements, hardware supported, software platform deferrals, and changes to the microcode and related documents.
Cisco IOS Release 12.0 ST3 is based on Cisco IOS Release 12.0S and Release 12.0, and is currently tailored to provide new MPLS features in service provider environments. Cisco IOS Release 12.0(11)ST3 is synchronized to Release 12.0(11)S. Release 12.0 S is the follow-on release to Release 11.1 CC, which was also targeted to the service provider environment. Additionally, many of the features in Release 12.0 S were first introduced for the Cisco 12000 series routers in Release 11.2 OS and for the Cisco 7000 family in Release 12.0 T.
Use these release notes in conjunction with the Release Notes for Cisco IOS Release 12.0 and Release 12.0 S, which are located on Cisco Connection Online (CCO) and the Documentation CD-ROM.
In addition to the caveats listed in the "Caveats" section, the software caveats that apply to Release 12.0 and Release 12.0 S also apply to Release 12.0 ST3. For information on other caveats that might apply to Cisco IOS Release 12.0 ST3, refer to the caveat documents for Release 12.0 and Release 12.0 S that are located on CCO and on the Documentation CD-ROM.
Contents
These release notes contain the following sections:
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Obtaining Technical Assistance
Introduction
Cisco IOS Release 12.0(11)ST3 is the first general availability release of this software. Release 12.0(11)ST3 is synchronized to Cisco Release 12.0(11)S. Many of the features and the hardware supported in this software have been previously released to customers. For information on new features and Cisco IOS commands supported by Release 12.0(11)ST3, see the "New and Changed Information" section and the "Related Documentation" section.
System Requirements
This section describes the following system requirements for Release 12.0(11)ST3:
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Memory Requirements
Table 1, Table 2, and Table 3 list the memory requirements for the platforms supported in Cisco IOS Release 12.0(11)ST3.
Table 1 Memory Requirements for the Cisco 7200 Series Platform
Flash MemoryService Provider
c7200-p-mz
16 MB
128 MB
RAM
Table 2 Memory Requirements for the Cisco 7500/RSP Series Platform
Flash MemoryService Provider
rsp-pv-mz
16 MB
128 MB
RAM
Table 3 Memory Requirements for the Cisco 12000/GSR Series Platform
Flash MemoryService Provider
gsr-p-mz
16 MB
128 MB
RAM
Hardware Supported
Cisco IOS Release 12.0(11)ST3 supports the following platforms:
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Note
Determining the Software Version
To determine the version of Cisco IOS software currently running on your Cisco router, log in to the router and enter the show version EXEC command. The following is sample output from the show version command. The version number is indicated on the second line.
Cisco Internetwork Operating System SoftwareIOS (tm) 7200 Software (C7200-P-M), Version 12.0(11)ST3, RELEASE SOFTWAREAdditional command output lines include more information, such as processor revision numbers, memory amounts, hardware IDs, and partition information.
Microcode Software
Table 4 lists the current microcode versions for the Cisco 7500/RSP series. This series includes the Cisco 7500 series routers.
Microcode software images are bundled with the system software image, except for the Channel Interface Processor (CIP) microcode (all system software images) and the Versatile Interface Processor (VIP) microcode (certain system software images). Bundling eliminates the need to store separate microcode images. When the router starts, the system software unpacks the microcode software bundle and loads the proper software on all the interface processor boards. VIP and VIP2 microcode is bundled into all Cisco 7500 series feature sets listed in Table 4.
For further information about the CIP microcode, refer to the Cisco document Channel Interface Processor Microcode Release Note and Microcode Upgrade Instructions.
Feature Set Tables
The Cisco IOS software is packaged in feature sets consisting of software images. Each feature set contains a specific set of Cisco IOS features.
Different platforms support different feature sets. Table 5, Table 6, and Table 7 list the newest features and feature sets supported by the Cisco 7200 series, the Cisco 7500/RSP series, and the Cisco 12000 series in Cisco IOS Release 12.0 ST. The tables use the following conventions:
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Table 5 Feature List by Feature Set for the Cisco 7200 Series
LC-ATM
11
Yes
Label Distribution Protocol MIB
11
Yes
Table 6 Feature List by Feature Set for the Cisco 7500/RSP Series
LC-ATM
11
Yes
Label Distribution Protocol MIB
11
Yes
New and Changed Information
Refer to the following section, "New Features in Release 12.0(11)ST3."
New Features in Release 12.0(11)ST3
Release 12.0(11)ST3 supports the following new features:
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Diff-Serv-aware Traffic Engineering
MPLS traffic engineering allows constraint-based routing of IP traffic. One of the constraints satisfied by CBR is the availability of required bandwidth over a selected path. Diff-Serv-aware Traffic Engineering extends MPLS traffic engineering to enable you to perform constraint-based routing of "guaranteed" traffic, which satisfies a more restrictive bandwidth constraint than that satisfied by CBR for regular traffic. The more restrictive bandwidth is termed a sub-pool, while the regular TE tunnel bandwidth is called the global pool. (The sub-pool is a portion of the global pool.) This ability to satisfy a more restrictive bandwidth constraint translates into an ability to achieve higher Quality of Service performance (in terms of delay, jitter, or loss) for the guaranteed traffic.
For example, DS-TE can be used to ensure that traffic is routed over the network so that, on every link, there is never more than 40 per cent (or any assigned percentage) of the link capacity of guaranteed traffic (for example, voice), while there can be up to 100 per cent of the link capacity of regular traffic. Assuming QoS mechanisms are also used on every link to queue guaranteed traffic separately from regular traffic, it then becomes possible to enforce separate "overbooking" ratios for guaranteed and regular traffic. (In fact, for the guaranteed traffic it becomes possible to enforce no overbooking at all or even an underbooking so that very high QoS can be achieved end-to-end for that traffic, even while for the regular traffic a significant overbooking continues to be enforced.)
Also, through the ability to enforce a maximum percentage of guaranteed traffic on any link, the network administrator can directly control the end-to-end QoS performance parameters without having to rely on over-engineering or on expected shortest path routing behavior. This is essential for transport of applications that have very high QoS requirements (such as real-time voice, virtual IP leased line, and bandwidth trading), where over-engineering cannot be assumed everywhere in the network.
DS-TE involves extending OSPF (Open Shortest Path First routing protocol), so that the available sub-pool bandwidth at each preemption level is advertised in addition to the available global pool bandwidth at each preemption level. And DS-TE modifies constraint-based routing to take this more complex advertised information into account during path computation.
In this release, tight guarantees can be achieved using the Cisco 12000 Gigabit Switch Router (GSR) and POS (Packet over SONET) interface, with Engine 0 line card at the edge and Engine 2 line card at the core. End-to-end guaranteed bandwidth service is achieved by applying CAR (Committed Access Rate) and MPLS QoS mechanisms in conjunction with DS-TE. QPPB (Qos Policy Propagation via BGP) is not supported with input CAR on the GSR in this release.
LC-ATM
The label-controlled ATM interface (LC-ATM) allows Cisco 12000 series routers to operate with the Cisco Label Switch Controller (LSC). The LSC must be running IOS Version 12.1(5)T or higher, and the Cisco 12000 series router must be running IOS Version 12.0(11)ST3 or higher.
Label Distribution Protocol MIB
Multiprotocol label switching (MPLS) is a packet forwarding methodology that uses a short, fixed-length value (called a label) in packets to enable the determination of the next hop for transporting packets through an MPLS network. Two label switching routers (LSRs) must agree on the definition of the labels used to forward network traffic between and through them. This common understanding of labels is achieved through a set of procedures embodied in the Label Distribution Protocol (LDP). The LDP enables an LSR to inform other LSRs of the label bindings it has made, thereby distributing label binding information to peer devices for the purpose of supporting hop-by-hop forwarding along normally routed paths.
In order for LDP to be used to the best advantage in an MPLS network, the MPLS Label Distribution Protocol MIB (MPLS LDP MIB) has been implemented in conjunction with MPLS and LDP. Designed as a network management aid, the MPLS LDP MIB is based on an Internet Engineering Task Force (IETF) draft that defines objects in a structured and standardized label-switching database.
The information in the MPLS LDP MIB is accessible by means of any network management utility that supports the Simple Network Management Protocol (SNMP). The SNMP-based code in a network management utility incorporates a layered structure for supporting the MPLS LDP MIB that is similar to that built into Cisco IOS software for supporting MIBs.
New MPLS VPN Line Card for GSR
MPLS-based VPNs on Engine 2 line cards support POS and DPT-48 technologies for customer access and for connection to the service provider's backbone. A maximum of 256 VPNs (16 x 16) can be configured on a GSR that is fully populated with 16xOC-3 Engine 2 line cards. A maximum of approximately 100K VPN routes can be configured on a GSR platform with Engine 2 line cards, when not using other MPLS applications such as CoS.
New MPLS VPN line cards supported for GSR include
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Restrictions in Release 12.0(11)ST3
This section describes the following:
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MPLS Class of Service Restriction
Although Class-Based Weighted Fair Queuing (CBWFQ) is available in Release 12.0(10)ST for Cisco 7500 series routers, it is not usable in Release 12.0(11)ST3. This feature is expected to be available again in the next release of 12.0ST.
Open Shortest Path First Restriction
Open Shortest Path First (OSPF) is not supported between customer edge (CE) to provider edge (PE) routers on GSR Engine 0 and Engine 2 line cards. Only Version 2 of the Routing Information Protocol (RIP), static routers, and external BGP are supported.
PIRC and Access Lists Restriction
GSR PIRC and access lists cannot be configured under VRF interfaces on a PE router.
New Features in Release 12.0(10)ST
Release 12.0(10)ST supports the following new features:
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Note
MPLS Traffic Engineering and Enhancements
MPLS traffic engineering software enables an MPLS backbone to replicate and expand upon the traffic engineering capabilities of Layer 2 ATM and Frame Relay networks.
Traffic engineering is essential for service provider and Internet service provider (ISP) backbones. Such backbones must support the use of a high percentage of transmission capacity, and the networks must be very resilient so that they can withstand link or node failures.
MPLS traffic engineering provides an integrated approach to traffic engineering. With MPLS, traffic engineering capabilities are integrated into Layer 3, which optimizes the routing of IP traffic, given the constraints imposed by backbone capacity and topology.
For more information, refer to the MPLS Traffic Engineering and Enhancements feature in Cisco IOS Release 12.0(10)ST.
MPLS Traffic Engineering Fast Reroute—Link Protection
MPLS Traffic Engineering Fast Reroute (FRR) delivers Layer 3 protection switching for networks currently configured with MPLS label switched paths (LSPs). MPLS Traffic Engineering FRR provides temporary rerouting around a failed link (in the future, a node). This protects against physical point-to-point link failures. Upon notification (such as loss of signal or loss of frame) of a facility, a path error failure is delivered to the LSP/tunnel headend and the logical LSP is rerouted to the next hop by way of a preconfigured backup LSP/tunnel.
Regular MPLS traffic engineering automatically establishes and maintains LSPs across the backbone using RSVP. The path used by a given LSP at any point in time is determined by the LSP resource requirements and network resources, such as bandwidth.
Available resources are flooded by means of extensions to a link-state based Interior Gateway Protocol (IGP), either IS-IS or OSPF.
Paths for LSPs are calculated at the LSP headend. Under failure conditions, the headend determines a new route for the LSP. Recovery at the headend provides for the optimal use of resources. However, due to messaging delays, the headend cannot recover as fast as possible by making a repair at the point of failure.
FRR provides link protection to LSPs. This link protection enables all the traffic carried by LSPs that traverse a failed link to be rerouted around the failure. The reroute decision is completely controlled locally by the router interfacing the failed link. The headend of the tunnel is also notified of the link failure through the IGP or through Resource Reservation Protocol (RSVP) and completely reroutes the LSP around the failure.
Note
For more information, refer to the MPLS Traffic Engineering Fast Reroute feature in Cisco IOS Release 12.0(10)ST.
MPLS Label Distribution Protocol
The MPLS Label Distribution Protocol (LDP) is the IETF standard protocol for label distribution. LDP provides the means for label switching routers (LSRs) to request, distribute, and release label prefix binding information to peer routers in a network. LDP is a two-party protocol that provides the means for LSRs to discover potential peers in a network and to establish LDP sessions with those peers for the purpose of exchanging label binding information.
Functionally, LDP is a superset of the prestandard Tag Distribution Protocol (TDP), which also supports MPLS forwarding along normally routed paths. In addition, for those features that LDP and TDP have in common, the pattern of protocol exchanges between platforms is identical. The differences between LDP and TDP for the features that both protocols support are largely embedded in their respective implementation details, such as the encoding of protocol messages.
This release, which supports both LDP and TDP, provides the means for transitioning an existing network from a TDP switching environment to an LDP switching environment. You can run LDP and TDP simultaneously on any given platform. The protocol that you use can be configured on a per-interface basis for directly connected neighbors and on a per-target basis for nondirectly connected (targeted) neighbors. In addition, an LSP across an MPLS network can be supported by LDP on some hops and by TDP on other hops.
For more information, refer to the MPLS LDP feature in Cisco IOS Release 12.0(10)ST.
MPLS for Cisco Routers
Note
MPLS combines the performance and capabilities of Layer 2 (data link layer) switching with the proven scalability of Layer 3 (network layer) routing. MPLS enables service providers to meet the challenges of explosive growth in network utilization while providing the opportunity to differentiate services without sacrificing the existing network infrastructure. The MPLS architecture is flexible and can be employed in any combination of Layer 2 technologies. MPLS support is offered for all Layer 3 protocols, and scaling is possible beyond that typically offered in today's networks.
MPLS efficiently enables the delivery of IP services over an ATM switched network. MPLS supports the creation of different routes between a source and a destination on a purely router-based Internet backbone. By incorporating MPLS into their network architecture, service providers can save money, increase revenue and productivity, provide differentiated services, and gain competitive advantages.
For more information, refer to the MPLS for Cisco Routers feature in Cisco IOS Release 12.0(10)ST.
VPN-Aware PING MIB
The ping MIB supports VPNs. An attribute, VrfName, has been added to the ciscoPingEntry in MIBS/CISCO-PING_MIB.my. This attribute allows the provider-edge router to look up the appropriate VPN routing table while sending a ping packet. If this attribute is NULL (default), a ping packet uses the default VPN routing table.
For descriptions of supported MIBs and how to use them, see the Cisco MIB web site on CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.
MPLS Egress NetFlow Accounting
The MPLS Egress NetFlow Accounting feature allows you to capture Internet Protocol (IP) flow information for packets undergoing MPLS label disposition - that is, packets that arrive on a router as MPLS and are transmitted as IP.
Prior to this feature, you captured NetFlow data only for flows that arrived on the packet in IP format. When an edge router performed MPLS label imposition (received an IP packet and transmitted it as an MPLS packet), NetFlow data was captured when the packet entered the network. Inside the network, the packet was switched based only on MPLS information; NetFlow information was not captured until after the last label was removed.
One common application of the MPLS Egress NetFlow Accounting feature allows you to capture the MPLS virtual private network (VPN) IP flows that are traveling through a service provider backbone from one site in a VPN to another site in the same VPN.
Formerly, you captured flows only for IP packets on the ingress interface of a router. You could not capture flows for MPLS encapsulated frames, which were switched through Cisco express forwarding (CEF) from the input port. Therefore, in an MPLS VPN environment you captured flow information as packets were received from a customer edge (CE) router and forwarded to the backbone. However, you could not capture flow information as packets were transmitted to a CE router because those packets were received as MPLS frames.
The MPLS Egress NetFlow Accounting feature lets you capture the flows on the outgoing interfaces.
For more information, refer to the MPLS Egress NetFlow Accounting feature in Cisco IOS Release 12.0(10)ST.
ATM Adaptation Layer Type 5 Transport over MPLS
The ATM Adaptation Layer Type 5 (AAL5) Transport over MPLS (AToM) feature provides an ATM permanent virtual circuit (PVC) transport service for transporting AAL5 protocol data units (PDUs) across an IP/MPLS backbone with rate-limit policing and a configurable PVC priority value. A dynamic MPLS tunnel is configured to enable label imposition and disposition of encapsulated ATM PDUs transported between two edge routers having a Label Distribution Protocol (LDP) neighbor relationship.
Each routed PVC label stack has two levels of labels prepended to each ATM PDU: an Internal Gateway Protocol (IGP) stack consisting of zero or more labels and a PVC-based label. Label imposition and disposition are performed by routers at the edge of the MPLS backbone. The imposition router takes the ATM PDU and encapsulates it in an MPLS PDU for transport to the correct disposition router. The disposition router takes the MPLS PDU, de-encapsulates the ATM PDU, and delivers it to the correct ATM interface and virtual path identifier/virtual circuit identifier (VPI/VCI).
For more information, refer to the ATM Adaptation Layer Type 5 Transport over MPLS feature in Cisco IOS Release 12.0(10)ST.
MPLS Class of Service
The MPLS class of service (CoS) feature enables network administrators to provide differentiated services across an MPLS network. A range of networking requirements can be satisfied by supplying for each packet transmitted the particular CoS specified for each packet by means of its CoS precedence bit setting. CoS services are differentiated by means of the IP precedence bit setting in each transmitted IP packet.
In providing differentiated IP services, MPLS CoS supports the following services:
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For more information, refer to the MPLS CoS feature in Cisco IOS Release 12.0(10)ST.
OSPF PE-CE Support
Setting a separate router ID for each interface or subinterface on a provider edge (PE) router attached to multiple CE routers within a VPN provides increased flexibility through Open Shortest Path First (OSPF) when routers exchange routing information among sites. The OSPF PE-CE feature is supported only on the Cisco 7000 family of routers (7200 and 7500).
For more information, refer to the MPLS Virtual Private Network Enhancements feature in Cisco IOS Release 12.0(7)T.
VRF CLI Command
The VPN routing/forwarding (VRF) configuration command allows you to enter comments about your VRF configuration.
description description_string
no description
Here is output from a configuration example:
Router(config)# ip vrf V4Router(config-vrf)# ?IP VPN Routing/Forwarding instance configuration commands:default Set a command to its defaultsdescription VRF specific descriptionexit Exit from VRF configuration modeexport VRF exportimport VRF importmaximum Set a limitno Negate a command or set its defaultsrd Specify Route Distinguisherroute-target Specify Target VPN Extended CommunitiesRouter(config-vrf)# descRouter(config-vrf)# description ?LINE Up to 80 characters describing this VRFRouter(config-vrf)# description This Is My 4th VRF ;-)Router(config-vrf)# endRouter# sh ru | beg V4ip vrf V4description This Is My 4th VRF ;-)rd 1:406route-target export 1:400route-target import 1:400VRF-Specific Static ARP Entry Support
The VPN routing/forwarding (VRF) option in the Address Resolution Protocol (ARP) command allows you to configure static ARP entries per VRF.
[no] arp [vrf name] ipaddr hardware-addr {arpa | sap | smds | snap} [{alias | interfaces}]
Here is output from a configuration example:
Router(config)# arp ?A.B.C.D IP address of ARP entryvrf Configure static ARP for a VPN Routing/Forwarding instanceRouter(config)# arp vrf V4 ?A.B.C.D IP address of ARP entryRouter(config)# arp vrf V4 20.1.1.1 0000.0000.0001 arpaNew MPLS VPN Line Card Support for GSR
New line cards supported for GSR include
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VPN Slow-Path Support on Engine 2 at Deaggregation Point (Between PE-P)
You can now have an Engine 2 card in the chassis when you are running VPN. However, full support will be available in a future release.
New Features in Release 12.0(9)ST
Release 12.0(9)ST supports the following new features:
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MPLS Support on Dynamic Packet Transport
Dynamic packet transport (DPT) offers the reliability and restorability typically associated with SONET/SDH transport, without adding unnecessary overhead to IP traffic.
DPT uses dual counter-rotating fiber rings that can concurrently transport data and control traffic. DPT uses the Spatial Reuse Protocol (SRP), which is the media-independent Media Access Control (MAC) layer protocol, for addressing and stripping packets, controlling bandwidth, and controlling message propagation on the packet ring.
Note
DPT (OC-12/STM4) is supported for forwarding and label distribution on the following:
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DPT combines the bandwidth-efficient and service-rich capabilities of IP routing with the bandwidth-rich, self-healing capabilities of fiber rings to provide fundamental cost and functionality advantages over existing solutions.
MPLS Traceroute
MPLS-aware traceroute functionality has been added to the traceroute program. When you enter the traceroute user EXEC command, the display output includes the IP address of the router interface through which the traceroute packet is passing, followed by the MPLS label information and the normal trace/ping information.
The following is sample output from the traceroute command:
Router-A# traceroute 14.0.0.1Type escape sequence to abort.Tracing the route to 14.0.0.11 10.0.0.2 [MPLS: Label 138 Exp 0] 0 msec 0 msec 4 msec2 11.0.0.2 [MPLS: Label 138 Exp 0] 0 msec 0 msec 0 msec3 14.0.0.1 4 msec 0 msecMPLS Virtual Private Networks
A virtual private network (VPN) is a secure IP-based network that uses a shared backbone to distribute resources on one or more physical networks located in geographically dispersed sites. MPLS-based VPNs make it possible to have highly scalable, highly flexible IP VPNs in Layer 3 without tunneling or encryption.
MPLS VPNs have the following advantages over the current IP VPN solutions that rely on Layer 2 VC, Layer 3 tunnels, or encryption:
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End users do not have to modify their IP applications or support MPLS.
MPLS-based VPNs support a variety of Layer 2 technologies (ATM, Frame Relay, Packet over SONET (PoS), and multi-access) for customer access, and in the provider's backbone.
Line cards supported for GSR include
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Multiprotocol BGP
Multiprotocol BGP provides extensions to BGP-4 as specified in IETF RFC 2283, Multiprotocol Extensions for BGP-4. T. Bates, R. Chandra, D. Katz, and Y. Rekhter. February 1998.
(Format: TXT=18946 bytes) (Status: PROPOSED STANDARD).These extensions enable multiprotocol BGP to carry different address families. In Release 12.0(9)ST, multiprotocol BGP supports the distribution of multicast and MPLS VPN routes. In the future, these multiprotocol BGP extensions will support the distribution of IPv6 routes.
Caveats
Caveats describe unexpected behavior in Cisco IOS software releases. Severity 1 caveats are the most serious; severity 2 caveats are less serious.
This section contains only open caveats for the current Cisco IOS 12.0(11)ST3 release.
Because Cisco IOS Release 12.0 ST and Release 12.0 S are based on Release 12.0, many caveats that apply to these releases apply to Release 12.0(11)ST3. For information on severity 1 and 2 caveats in Cisco IOS Release 12.0, see Caveats for Cisco IOS Release 12.0. It is located on CCO and the Documentation CD-ROM.
Note
Note
Open Caveats for Release 12.0(11)ST3
This section describes possibly unexpected behavior by Release 12.0(11)ST3. This section describes only severity 1 and 2 caveats. The caveats are as follows:
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SNMP string function correction.
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Deletion of the tunnel interface in an MPLS traffic engineering tunnel headend router might cause CPUHOG messages if there are lots of routes (thousands) going over the tunnel.
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Online insertion and removal (OIR) does not work for a Raptor card.
Workaround: Reload microcode for the card or reload the router if it does not recover.
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GSR Engine 0 and Engine 2 line cards reload if you configure MPLS COS WRED for transmit link queues by using the tx-cos command on a tunnel interface.
Workaround: Do not use the tx-cos command on a tunnel interface. Use the command at the tunnel's associated physical interface.
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Deleting and then putting back a BGP address family for a VPN causes a permanent interruption of the connectivity within the customer edge routers (CEs) of that VPN.
Workaround: Clear all VRF routes in that VPN.
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An MPLS LSR at the headend of a traffic engineering tunnel might have the following problem when running Release 12.0(10.6)ST or later:
A show tag forwarding prefix detail for a prefix routed over the tunnel might show more than one tagged path to that prefix. However, the extra path(s) are not used for forwarding. This is evident by observing the "slots" entry corresponding to the extra path in the command output. The extra paths do not use any slots.
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When you reconfigure the bandwidth of any equal cost tunnels, loadsharing does not update properly for routes dependent on MPLS tunnels.
Workaround: After you reconfigure the bandwidth, enter the clear ip route dest command. Alternatively, shut down the tunnel before reconfiguring the bandwidth.
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Interprocess communication (IPC) blocking error messages might appear during heavy traffic load conditions or when physical interfaces are flapping. This might lead to loss of connectivity.
Workaround: Reload the microcode for the line card generating the errors if connectivity is lost.
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When 100+ MPLS traffic engineering tunnels are set up in a short span of time among a set of routers, the headend router might issue a TFIB-7-SCANSABORTED message. This typically means that the TFIB module is repeatedly getting requests to suspend its current scan and start a new one. This might delay the tunnels coming up; however, in most cases this should not impair functionality.
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The following new show command assumes the global bandwidth pool. It does not display information for tunnels using sub-pool bandwidth.
show mpls traffic-eng tunnels suboptimal constraints•
Sometimes a headend router that is load sharing across multiple MPLS traffic engineering tunnels puts the wrong label on some packets.
Workaround: Do not load share across multiple tunnels.
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The following line cards for the Cisco 12000 series routers do not properly support MPLS fragmentation:
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On GSR FE/GE line cards with the baby giant feature, the maximum Ethernet frame size is 1522 bytes; that is, one label (4 bytes).
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The Cisco express forwarding (CEF) entries for remote VRF site prefixes are withdrawn when the last CE-PE interface in a VRF is shut down in the local PE. All these remote VRF prefixes become unreachable from the local PE.
Workaround: Toggle the CE-PE ATM subinterface to restore the MPLS information in CEF.
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A Cisco 7200 series router configured with 250 ATM Address Resolution Protocol (ARP) clients might reload during a stress test.
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A GSR ATM interface used for MPLS can not use the entire virtual path identifier (VPI) range configured on the subinterface. Attempts to create label switched controlled virtual circuits (LVCs) within the configured range may be rejected by the line card drivers. This may occur when using the GSR ATM OC-3 or OC-12 interfaces running MPLS.
Workaround: To obtain the optimal LVC space, specify the following configurations on the GSR interfaces:
For the quad OC-3 or quad OC-12
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atm vc-per-vp 512–
mpls atm control-vc 2 32
mpls atm vpi 2-8
For the single-port OC-12
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atm vc-per-vp 1024–
mpls atm control-vc 2 32
mpls atm vpi 2-16You must configure the control-vc of the TDP neighbor so that it uses the same VPI and VCI.
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Some route memory on GSR Engine 2 line cards is allocated, by default, by the PSA ACL application.
Workaround: To reach the maximum number of VPN routes on a GSR platform (100K), include the following CLI command in the router configuration: no access-list hardware psa
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When Scepter is configured for MPLS/VPN at the imposition side, under certain conditions, such as when a heavy load of traffic is sent at small packet sizes or when physical interfaces are flapping under traffic, line cards might eventually crash.
Workaround: Rate limit (police) incoming traffic to the PE router and turn off Keepalives.
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No packets match if config input CAR rate policy "qos-group" and set mpls-exp are in one CAR command.
Workaround: Separate the config into two commands.
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An LSR in an MPLS network is configured to summarize routes. A neighbor router of an LSR that summarizes routes may use the wrong outgoing label for one or more of the summarized routes.
Workaround: Do not configure route summarization on an MPLS LSR.
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Symptom: The state of AAL5 over MPLS (AToM) tunnels configured on a Cisco Gigabit Switch Router (GSR) is changed to DOWN when any Multiprotocol Label Switching (MPLS) Traffic Engineering (TE) tunnels are configured between the same source and destination GSR. This happens for any number of MPLS TE tunnels and is not a scalability issue.
Workaround: There are two workarounds for this problem.
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config terminalinterface tunnel xyzno tunnel mpls traffic-eng autoroute announce–
ip route A.B.C.D E.F.G.H tunnel xyz A.B.C.DResolved Caveats—Release 12.0(11)ST3
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A Cisco router might reload if you enter the show ip cef EXEC command while the routing table is changing.
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The BGP Site of Origin (SOO) attribute is not added to some prefixes.
Workaround: Perform a Border Gateway Protocol (BGP) soft reset, using the clear ip bgp soft EXEC command (if soft reconfiguration is configured).
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When multiple load-shared paths exist between provider edge (PE) routers, a PE router might reload if all paths are lost simultaneously while Virtual Private Network (VPN) traffic is being forwarded.
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Affected platforms: This caveat affects only the 12016 GSR+ product, due to its unique power supply architecture.
Symptoms: Frequent spurious over/under voltage and over-temperature alarms occur, seemingly at random. The show environment commands return invalid values. MIB readings from the powershelf are wrong. A real over-voltage or over-temperature condition might be missed or ignored due to frequent false alarms on perfectly functional shelves.
Workarounds: None. Users of 12016 GSR+ products should obtain the bug fix as soon as operationally convenient to reduce possible missed notifications of valid environmental problems, as well as recurring spurious reports of trouble.
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When a Packet-over-SONET (POS) interface with an OC-48c/STM-16 POS line card on a Cisco 12008 series GSR router is disconnected and then reconnected, the router might stop functioning and display continuous "%LC-2-INTSCHED" messages and traceback output messages. This may also occur when the other end of the POS line is a Cisco 120008 router that goes down/up. A side effect is a memory loss in the IS-IS update process.
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A GSR router running Release 12.0(9.6)ST3 with DC power supplies displays the following messages repeatedly, but does not shut down:
GSR_ENV-0-SHUTDOWN: Slot 24 Inlet sensor temperature at 33 deg C > 0 deg C
GSR_ENV-0-SHUTDOWN: Slot 24 48V supply at 50V < 65408 V
This does not happen with AC power supplies.
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A Cisco 12000 series GSR router configured with an 8-port fast Ethernet card might experience ARP table corruption if it is connected to specific types of Xyplex terminal servers. To view the corrupted values, enter the show ip arp command to view the ARP table for the interface. The corrupt MAC address might contain 0f00 as the final two octets.
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If a Cisco 12000 series GSR router is configured with access control lists (ACLs) that are longer than 128 lines, and those ACLs are on an ingress Engine 2 (PSA-based) line card interface, traffic that is destined for the router might be dropped. This affects traffic such as Internet Control Message Protocol (ICMP), Simple Network Management Protocol (SNMP), and routing protocol updates. This situation exists on Engine 2 (PSA) line cards only when an ACL longer than 128 lines is applied inbound.
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Under certain conditions, Cisco IOS might incorrectly detect the type of power supply (AC or DC) in the GSR router.
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A Cisco 12000 series Gigabit Switch Router (GSR) might reload unexpectedly if all multiprotocol label switching (MPLS) traffic engineering (TE) tunnels are removed. This situation occurs during heavy load conditions (for example, when several thousand routes and several hundred TE tunnels are removed).
Workaround: Wait a couple of seconds between removing tunnels.
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A single line card can not connect two CE routers and the P router of the same VPN. This restriction applies only to connections that are members of the same VPN.
Workaround: Move one of the CE routers or the P router to another line card
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When modifying a tunnel that uses global-pool bandwidth to use sub-pool bandwidth instead, the tunnel may go down (even though there is sufficient sub-pool bandwidth).
Workaround: First shut down the tunnel, and then modify the bandwidth pool and bring the tunnel back up.
When tunnels using global-pool and sub-pool bandwidth are created quickly (back-to-back) and use the same setup/hold priorities, some tunnels may not come up right away (even though there is sufficient bandwidth in both pools). After the IGP update is received, they will come up.
Workaround: Wait for the IGP update, or wait between tunnel creation.
It is unlikely that customers will encounter these problems because they generally use different priorities for tunnels using different pools, and they do not frequently modify the bandwidth pool that a tunnel uses.
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Symptom: The outgoing tag field for the tag forwarding table entry for a destination is "Untagged" when it should be either a specific tag or "Pop tag." (The command show tag-switching forwarding displays the tag forwarding table.) When this occurs, traffic for the destination may be dropped.
Conditions: The symptom may occur on Cisco routers with tag-switching ip enabled.
Workaround: The following procedure may correct this problem:
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A Cisco Gigabit Switch Router (GSR) can, during heavy load conditions with several thousand BGP routes and line rate traffic, have extended traffic disruption. This is more likely to happen when the router contains hundreds of MPLS traffic engineering tunnel heads.
Workaround: Slow incoming traffic to the router significantly. When the traffic flow is reestablished, restart the full traffic flow. It might be necessary, in extreme cases, to reload a line card with the microcode reload slot command.
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A router running Cisco IOS Release 12.0(12.3)S might experience problems forwarding non-GRP-sourced traffic from POS line cards. All traffic from external sources being forwarded through those line cards will be dropped without any indication in the counters or elsewhere. Traffic generated by the router's GRP (ICMP packets and BGP/OSPF protocol traffic) is not affected by this problem.
Workaround: Shut down all POS interfaces that do not have an IP address set. If the problem already occurred, reload the line card.
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This problem might occur in MPLS networks using LDP (or TDP) that have routes for both 0.0.0.0./0 (the default) and 0.0.0.0/n. In an MPLS network using LDP (or TDP), packets matching the default route are dropped or forwarded incorrectly. On routers incorrectly dropping or forwarding such packets, the output of the show tag-switching forwarding command or the show mpls forwarding command shows the label advertised for 0.0.0.0/n as the outgoing label for 0.0.0.0/0.
Workaround: Prevent use of route 0.0.0.0/n in networks that use 0.0.0.0./0 (the default).
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This problem might occur when running TDP on an ATM point-to-point subinterface between two routers. The problem has been observed only with IOS Version 12.1(5a). The TDP session for the subinterface disappears for no apparent reason and cannot be reestablished.
Workaround: No workaround has been tested and verified because the behavior has not been reproduced. However, the following sequence of commands executed on both routers might correct the situation:
configure terminalinterface interface_nameshutWait for 10 to 15 seconds.
no shut•
When a GSR router is being used in both MPLS VPN and tag switching functionality, Engine 0 line cards can not properly forward some MPLS packets.
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An Engine 2 Packet over Sonet (POS) line card on a Cisco Gigabit Switch Router (GSR) might have disrupted traffic during heavy load conditions with several thousand BGP and IGP routes and line rate traffic. This is more likely to happen when hundreds of multiprotocol label switching (MPLS) traffic engineering tunnel headpoints are configured on the router.
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Engine 2 Packet over Sonet (POS) line cards on a Cisco Gigabit Switch Router (GSR) may be severely affected and may be reset if hundreds of multiprotocol label switching (MPLS) tunnel interfaces are unconfigured simultaneously during heavy stress conditions with several thousand BGP and OSPF routes and line rate traffic. This is most likely to happen if the IGP is IS-IS.
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Cisco 12000 series routers running Release 12.0(14)S1, 12.0(14)S2, 12.0(13.6)ST3, or 12.0(14.3)S might reload with one of the following error messages:
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virtual addr 0x2809100E, physical addr(21:3) 0x091008, vAddr(14:12) 0x1000
virtual address corresponds to unknown, cache word
Address: 0x28091000 not in L1 Cache
Address: 0x2809100E Can not be loaded into L1 Cache–
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Workaround: Upgrade to Release 12.0(15)S or Release 12.0(14)ST.
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Forwarding MPLS traffic over a GRE tunnel does not work. Traffic is dropped at the imposition router.
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An MPLS VPN provider edge router running Release 12.0(9.6)ST6 or later might crash while performing label imposition on the VPN traffic if its TDP/LDP session with the downstream router ever flaps.
Related Documentation
The following sections describe the documentation available for the Cisco 7000 family and Cisco 12000 series routers. These documents consist of hardware and software installation guides, Cisco IOS configuration and command reference publications, system error messages, feature modules, and other documents.
Documentation is available as printed manuals or electronic documents except for feature modules, which are available online on CCO and the Documentation CD-ROM.
Use these release notes with these documents:
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Release-Specific Documents
The following documents are specific to Release 12.0 and are located on CCO and the Documentation CD-ROM:
Note
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On CCO at
Technical Documents > Documentation Home Page > Cisco IOS Software Configuration > Cisco IOS Release 12.0 > Release Notes > Cross-Platform Release Notes
On the Documentation CD-ROM at
Cisco Product Documentation > Cisco IOS Software Configuration > Cisco IOS Release 12.0 > Release Notes > Cross-Platform Release Notes
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Technical Documents
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As a supplement to the caveats listed in the "Caveats" section in these release notes, see Caveats for Cisco IOS Release 12.0, which contains caveats applicable to all platforms for all maintenance releases of Release 12.0.
On CCO at
Technical Documents > Documentation Home Page > Cisco IOS Software Configuration > Cisco IOS Release 12.0 > Caveats
On the Documentation CD-ROM at
Cisco Product Documentation > Cisco IOS Software Configuration > Cisco IOS Release 12.0 > Caveats
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Platform-Specific Documents
These documents are available for the Cisco 7000 family and Cisco 12000 series routers on CCO and the Documentation CD-ROM:
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On CCO at
Technical Documents > Documentation Home Page > Core/High-End Routers
On the Documentation CD-ROM at
Cisco Product Documentation > Core/High-End Routers
Feature Modules
Feature modules describe new features supported by Release 12.0 S and Release 12.0 ST; they are updates to the Cisco IOS documentation set. A feature module consists of a brief overview of the feature, benefits, configuration tasks, and a command reference. As updates, the feature modules are available online only. Feature module information is incorporated in the next printing of the Cisco IOS documentation set.
On CCO at
Technical Documents > Documentation Home Page > Cisco IOS Software Configuration > Cisco IOS Release 12.0 > New Feature Doc
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