LAB TESTING SUMMARY REPORT

Transcription

1 Key findings and conclusions: Cisco Nonstop Forwarding with Stateful Switchover drastically reduces mean time to repair (MTTR) Delivered zero route flaps with BGP, OSPF, IS-IS and static routes during recovery LAB TESTING SUMMARY REPORT April 2002 Report Product Category: Edge and Core Routers Vendor Tested: Cisco Systems Products Tested: Cisco and Series Internet Routers and Cisco 7500 Series Router Maintained state and showed zero link flaps during recovery for multiple protocols including Frame Relay, ATM, HDLC, PPP and Ethernet Cisco experienced no packet loss during route processor switchover, resulting in uninterrupted voice and video transmission Cisco Systems engaged Miercom to conduct analysis and performance validation tests of its Cisco Nonstop Forwarding (NSF) with Stateful Switchover (SSO) capabilities, which are part of Cisco Globally Resilient IP Technologies. The goal of testing was to validate switchover times during a route processor failure on three Cisco edge routers: the Cisco Series Internet Router, Cisco Series Internet Router and Cisco 7500 Series Routers, each of which displays different strengths at the edge. Tests were conducted with 600 interfaces; 2,000 OSPF or IS-IS routes; and 65,000 BGP routes on each router. We measured mean time to repair (MTTR) times in seconds on all three routers during simulated hardware and software failures. Results showed that the Cisco Series Internet Router recovered instantly with zero packets lost; the Cisco Series Internet Router recovered in an average of 1.63 seconds, and the Cisco 7500 Series Router recovered in an average of 6 seconds. (See chart below for comparisons between Cisco NSF with SSO and Cisco s previous best recovery mechanism Route Processor Redundancy+.) MTTR (seconds) Recovery Time Comparisons: Cisco Route Processor Redundancy+ versus Cisco NSF with SSO* Cisco Cisco Cisco *A comparison of average mean times to repair (MTTR) from system failure and begin passing traffic. Cisco NSF with SSO is compared to Cisco Route Processor Redundancy+, the best form of redundancy available on the Cisco and Series Internet Routers and 7500 Series Routers prior to the release of Cisco NSF with SSO.

2 Test-bed Setup About the testing The test bed was constructed in a network with sufficient port density and variety to demonstrate that Cisco NSF with SSO works simultaneously across a wide array of interfaces and protocols. We conducted three series of tests on each of the following: Cisco Internet Router, Cisco Series Internet Router and Cisco 7500 Series Routers. Cisco NSF with SSO was configured on each tested router and on all adjoining routers. It was disabled only when running baseline tests using Route Processor Redundancy+. In all tests, an Ixia 1600 was configured to transmit bi-directional traffic over all the links and ports of the Unit Under Test (UUT). The UUT was always configured for Cisco NSF with SSO. At the start of each test, the Ixia route advertisements, traffic flows and pings were started. Once traffic was verified as flowing, a failure was induced in the primary route processor and its impact observed on the traffic flows, links and routes. At the conclusion of the test, the primary route processor automatically restarted and established itself as the secondary processor. All tests were first conducted with IS-IS, and upon completion, the routers were reconfigured and all tests rerun using OSPF. As a second verification, a ping was set up from Enterprise Access1 (ENT1) to Core1 via the UUT. The ping was monitored during the switchover to measure the seconds of packet loss, One ping per second (per/sec) was sent. Link and route flaps were monitored through observation on the ENT and Core router consoles. In the final series of tests, the UUT was reconfigured to disable Cisco NSF with SSO and operate in Route Processor Redundancy+ mode. Tests were then re-executed, and the recovery time of a ping from ENT1 to Core1 via the UUT was observed and compared to recovery times that were observed when running Cisco NSF with SSO. Cisco Series Internet Router: The service provider distribution layer (Core1, Core2) consisted of two Cisco Internet Routers. The enterprise access layers (ENT1, ENT2, ENT3) consisted of two Cisco Internet Routers and a Cisco 7200 Series Router. The UUT was a Cisco Internet Router. On layers 1 and 2, ENT1, a Cisco Internet Router connected 81 T1s, 24 DS0s and 12 DS3s via three channelized DS3 links and a channelized OC-12 link to the UUT, which in all tests was configured for Cisco NSF with SSO. ENT2 (a Cisco Internet Router) connected 3 x OC-3 ATM links with 125 Permanent Virtual Circuits (PVCs) each, for a total of 375 subinterfaces. ENT3 (a Cisco 7200 Internet Router) connected 81 T1 links and 24 DS0 links via 3 channelized DS3 links to the UUT. There were 2 x OC-12 POS connections from the Core1 Core2 layers to the UUT. The total port count to the UUT was 599 ports, plus 1 loopback interface. The ATM interfaces were running aal5snap encapsulation. On the serial connections, 210 connections were using PPP and 12 were using HDLC, both with keepalives enabled. If SSO failed to reestablish and control the serial links, the timers caused link flaps. In addition to the routes required to pass traffic on all interfaces, an additional 65,000 overlapping BGP background routes were injected into Core1 and Core2 from the Ixia, forcing the processor to handle route re-convergence in a failover condition. The UUT handled 65,000 overlapping background BGP routes; 2,000 IS-IS or OSPF routes; and 1,311 BGP routes. In addition to the traffic streams, video and voice over IP (VoIP) streams were also set up to traverse the UUT. During the failover, the video stream was closely monitored for any disruptions or degradation of quality. An interactive conversation was also held on the VoIP system to determine if there was any disruption or degradation during failover. Cisco Series Internet Router: The Core consisted of a router, while a Internet Router represented the enterprise access layer (ENT1). The UUT was a Internet Router. On layers 1 and 2, 622 interfaces were connected to the UUT via 5 channelized DS3s from the ENT1. These enterprise interfaces (ENT1) were configured as 504 T1s using PPP encapsulation and 112 T1s using Frame-Relay encapsulation. Six additional clear channel DS3 interfaces had HDLC encapsulation. The Core router was connected to the UUT using a Gigabit Ethernet interface. In addition to the routes required to pass traffic on all interfaces, an additional 65,000 BGP background routes were injected into the core from the Ixia, forcing the processor to handle route re-convergence in a failover condition. The UUT handled 65,000 background BGP routes; 2,004 ISIS or OSPF routes; and 1,232 BGP routes. Cisco 7500 Series Router: ENT1 consisted of a Cisco 7513 Internet Router while Core1 and Core2 each included two Cisco 7513 Internet Routers. On layers 1 and 2, a total of 576 interfaces were connected to the UUT via an ATM OC-3, channelized T3 and E3 connection from ENT1. The enterprise interfaces were configured as 336 ATM PVCs and 112 serial connections from the T3 link and 128 serial connections from the E3 link. The core was connected to the UUT via 4 x OC-3 POS interfaces, two from each router. In addition to the routes required to pass traffic on all interfaces, an additional 65,000 BGP background routes were injected into the core (32,500 to each router) from the Ixia, forcing the UUT processor to handle route re-convergence in a failover condition. The UUT handled 65,000 background BGP routes; 2,000 ISIS or OSPF routes; and 1,152 BGP routes. Copyright 2002 Miercom Core/Edge Routers Page 2

3 Background Cisco Software Release 12.0(22)S with Cisco NSF with SSO provides full and automatic recovery from catastrophic route processor failures in routers equipped with redundant route processors (RPs). The technology is now available on Cisco 12000, and 7500 series edge and core routers, which were tested in this review. (See About the testing, page 2, for a detailed description of the test methodology and implementation.) Cisco NSF with SSO will be supported for Cisco 6500 and 7600 routers in future Cisco IOS Software releases. Cisco NSF with SSO allows uninterrupted IP packet forwarding while the IP routing protocols converge in the background. It is available for BGP, OSPF and IS-IS routing protocols. Tests were conducted using all three. Benefits: The major benefit of Cisco NSF with SSO is dramatically reduced downtime in the event of route processor failure, which can drive down operational expenses and reduce impact on in-service traffic. In addition, the higher levels of availability facilitate the deployment of IP-based services, such as voice, video and other missioncritical services, including virtual private networks. A proper deployment of Cisco NSF with SSO can result in the elimination of link and route flaps, packet loss and associated downtime in the event of a failure in hardware or software. Target environments: Cisco NSF with SSO is typically deployed in large IP networks with single points of failure. This includes service provider edge access sites, which supply connectivity to enterprise customers; enterprise edge environments with high-speed links; and businesses providing crucial services with uninterrupted access, such as Web hosts, commercial-class voice, stock trading, etc. In these environments conventional redundancy techniques, such as multihoming, are unavailable or too expensive to implement. The Advantages of Single Route Processor versus Dual Route Processor Single Route Processor Failure detection: Trouble-shooting required to isolate router failure Hardware replacement: Part replacement requires dispatching a technician and possibly reconfiguring the network if router is replaced System initialization: Cisco IOS must be loaded on the route processor and in the case of a distributed system - on any of the various line cards within the chassis. The Cisco IOS configuration file must be parsed, and memory allocation for any configured services must occur. Link re-establishment: All link-layer protocol state is lost during failure; Layer 2 link flaps may require significant work to re-establish state at higher layers of the OSI model. Routing convergence: No packet forwarding until routing protocols re-converge Resumption of forwarding: Packet forwarding resumes only after all routing protocols are converged and best-path calculations performed Dual Route Processor Immediate failover to secondary RP upon hardware or software failure in primary RP Standby router assumes role of primary router, eliminating any downtime for repairs Cisco IOS software is pre-loaded on standby RP. Checkpoint facility provides initial exchange of configuration file upon start-up, and subsequent configuration changes are communicated to the standby router as they occur. Line cards in distributed system never reset. Link-layer protocol information shared between primary and standby RPs is constantly updated; link state maintained across an RP failure; link re-establishment is not required Dependence upon converged routing protocol to maintain packet forwarding during RP switch-over eliminated Packet forwarding is uninterrupted before, during and after RP switchover Copyright 2002 Miercom Core/Edge Routers Page 3

4 Performance Results Cisco Systems contracted Miercom to test the IP resiliency features in Cisco IOS Software Release 12.0(22)S on the Cisco Series Internet Router, Cisco Series Internet Router and Cisco 7500 Series Router. Testing focused on Cisco NSF with SSO features, which are designed to greatly decrease MTTR. During testing, we created a simulated network consisting of a network core, unit under test (UUT) and an enterprise edge network. On all platforms, 65,000 BGP and 2,000 OSPF or IS- IS routes were injected into the UUT via the core network. From the enterprise, about 600 links were made via ATM and serial connections. Traffic was passed bi-directionally between the core network and enterprise devices through the UUT. A failover was then induced in the primary RP of the UUT, and the effects on the traffic and neighboring routers were observed. On all three routers, results showed a dramatic improvement in failover times when compared to Route Processor Redundancy+ mode, the best form of redundancy available on these Cisco routers prior to the introduction of Cisco NSF with SSO. All three routers had MTTR times over 30 seconds when running in Route Processor Redundancy+ mode, but MTTR times ranged from zero seconds to a high of only 6.57 seconds with Cisco NSF with SSO. (See graph, page 1.) The goal of testing three Cisco routers was to demonstrate the Cisco NSF with SSO would work simultaneously across a wide variety of interfaces and protocols in a network with no packet loss, route flaps or link flaps. Cisco Series Internet Router: Cisco NSF with SSO dramatically reduced failover times compared to those observed using Route Processor Redundancy+ mode. Specifically, failover occurred with no interruption to data streams and with no packet loss. In addition, an interactive VoIP call and video stream showed no discernable disruption of either voice or video communications during the RP switchover. Furthermore, neither the enterprise nor the core router reported route or link flaps. (Tables 1 and 2 illustrate specific results when running IS-IS and OSPF routing protocols.) Table 1: Cisco MTTR Using IS-IS Routing Protocol Run Failure Type Packet Loss Video Phone Link Flaps Route Flaps 1 Software induced 0 No impact Software induced 0 No impact Software induced 0 No impact Software induced 0 No impact No impact Software induced 0 No impact Pulled card 0 No impact Software induced 0 No impact Table 2: Cisco MTTR Using OSPF Routing Protocol Run Failure Type Packet Loss Video Phone Link Flaps Route Flaps 1 Software induced 0 No impact Software induced 0 No impact Software induced 0 No impact No impact Software induced 0 No impact Pulled card 0 No impact Software induced 0 No impact Copyright 2002 Miercom Core/Edge Routers Page 4

5 Table 3: Cisco MTTR Using IS-IS Routing Protocol* Run Failure Type Pings Lost from Pings from Core Link Flaps Route Flaps Enterprise 1 Software induced Software induced Software induced Software induced Software induced Pulled card Average: * Results obtained running OSPF were similar. Table 4: Cisco 7500 MTTR Using OSPF Routing Protocol* Run Failure Type Pings Lost Pings Lost Pings Lost from Link Flaps Route Flaps from ENT1 from ENT2 Provider 1 Software induced Software induced Software induced Software induced Software induced Average: *Results obtained running IS-IS were similar. Performance Results continued Cisco Series Internet Router: Results of testing showed a dramatic improvement in failover times when Cisco NSF with SSO was deployed. The Cisco Series Internet Router demonstrated an average failover time of 1.63 seconds with Cisco NSF with SSO, compared to an average 35-second failover time when tested in Route Processor Redundancy+ mode. In addition, the enterprise and core routers reported no route or link flaps during any of the tests in which Cisco NSF with SSO was enabled. Cisco 7500 Series Router: Results of testing also showed a dramatic improvement in failover times when using Cisco NSF with SSO. The Cisco 7500 Series Router demonstrated an average failover time of 6.0 seconds, compared to an average 30-second failover time when tested in Route Processor Redundancy+ mode. No route or link flaps were reported during any of the tests. Cisco and Series Internet Routers and 7500 Series Router: Key Features Platforms tested Interfaces tested Operating system Redundancy Price (US list) of system Cisco (10 chassis slots), Cisco (8 chassis slots) and Cisco 7513 (13 chassis slots) Cisco 12410: 6-port channelized DS3, 4-port OC-3 ATM, channelized OC-12- >DS3, 2 x single port OC-12 POS; Cisco 10008: 6-port channelized T3, 1 port GigE; Cisco 7513: PA-MC-T3, PA- A3-OC3, PA-FE, PA-POS-OC3. Cisco IOS software 12.0(22)S Fans, power supplies, route processors on all platforms; Switch Fabric and Clock Scheduler on Cisco Prices start at $120,000 for Cisco 12410; $38,750 for Cisco and $14,000 for the Cisco 7513 Cisco, Cisco IOS Software, Cisco Systems, and the Cisco Systems logo are registered trademarks of Cisco Systems, Inc., and/or its affiliates in the U.S. and certain other countries. Copyright 2002 Miercom Core/Edge Routers Page 5

6 Conclusions Performance testing conducted by Miercom demonstrated that Cisco NSF with SSO, which is part of Cisco IOS Software Release 12.0(22)S and the Cisco Globally Resilient IP technologies, greatly increases the availability of Cisco routers by decreasing the MTTR in the event of a route processor failure. Testing was conducted on the Cisco Series Internet Router, Series Internet Router, and Cisco 7500 Series Routers. Results of tests on all three routers showed that deploying Cisco NSF with SSO provided dramatically improved failover times (compared to Route Processor Redundancy+ mode). Cisco Systems, Inc. 170 West Tasman Drive San Jose, CA Phone: Fax: About Miercom s Product Testing Services With hundreds of its product-comparison analyses published over the years in such leading network trade periodicals as Business Communications Review, Network World, and Internet Week, Miercom s (formerly MIER Communications ) reputation as the leading, independent product test center is unquestioned. Founded in 1988 by Edwin E. Mier, formerly managing editor of Data Communications magazine and a practicing network consultant for over 20 years, the company has pioneered the comparative assessment of networking hardware and software, having developed methodologies for testing products from ATM switches to VoIP gateways and IP PBXs. Miercom s private test services include competitive product analyses, as well as individual product evaluations. Products submitted for review are typically evaluated under the NetWORKS As Advertised program, in which networking-related products must endure a comprehensive, independent assessment of the products usability and performance. Products that meet the appropriate criteria and performance levels receive the NetWORKS As Advertised award and Miercom Labs testimonial endorsement. 410 Hightstown Road, Princeton Junction, NJ fax Report Copyright 2002 Miercom Core/Edge Routers Page 6