- Preface
- New and Changed Information
- Understanding the Carrier Packet Transport System
- Hardware
- Configuring Ethernet Virtual Circuit
- Configuring Multiprotocol Label Switching
- Configuring MPLS–Transport Profile
- Configuring Pseudowire
- Configuring Virtual Private LAN Services
- Configuring Quality of Service
- Configuring High Availability
- Configuring Resilient Ethernet Protocol
- Configuring Link Aggregation Group and Link Aggregation Control Protocol
- Configuring Span
- Configuring MAC Learning
- Configuring Multicast VLAN Registration
- Configuring IGMP Snooping
- Configuring Ethernet OAM, Connectivity Fault Management, and Y.1731
- Configuring Synchronous Ethernet
- Configuring Performance Monitoring, RMON, OTN, and Port Provisioning
- Configuring Local Authentication
- Configuring Cisco Discovery Protocol
- Alarm Troubleshooting
- SNMP
- CPT Error Messages
- Support for MSTP Cards
- Network Element Defaults
- Index
Contents
- Configuring High Availability
- Stateful Switchover
- SSO Synchronization
- Redundancy Modes
- Switchover Operation
- NTP-J17 Manage SSO
- DLP-J46 Perform a Manual Switchover Using CTC
- DLP-J47 Verify SSO Configuration Using Cisco IOS Commands
- DLP-J48 Verify SSO Configuration Using CTC
- Examples of SSO Configuration
- Possible SSO Problem Situations
- DLP-J49 Troubleshoot SSO Using Cisco IOS Commands
- SSO Aware Protocols and Applications
- Active-Active Data Path
- Nonstop Forwarding
- NTP-J18 Manage NSF
- DLP-J50 Verify Cisco Express Forwarding NSF Using Cisco IOS Commands
- DLP-J51 Configure OSPF for NSF Using Cisco IOS Commands
- DLP-J52 Verify OSPF for NSF Using Cisco IOS Commands
- Examples of the NSF Configuration
- DLP-J53 Troubleshoot NSF Using Cisco IOS Commands
- In-Service Software Upgrade
- Graceful Restart
Configuring High Availability
This chapter describes Stateful Switchover, Cisco Nonstop Forwarding, and In-Service Software Upgrade. This chapter also describes the configuration procedures.
This chapter includes the following topics:
- Stateful Switchover
- Active-Active Data Path
- Nonstop Forwarding
- In-Service Software Upgrade
- Graceful Restart
Stateful Switchover
Stateful switchover (SSO) ensures state synchronization and non-disruptive switchover from an active to a standby fabric card, thereby providing an increase in both system and network availability. In SSO, the standby fabric card is fully initialized and is ready to assume control from the active fabric card when the switchover occurs.
SSO is particularly useful at the network edge. Traditionally, core routers protect against network faults using router redundancy and mesh connections that allow traffic to bypass failed network elements. SSO provides protection for network edge devices with dual route processors (RPs) that represent a single point of failure in the network design, and where an outage might result in loss of service for customers.
Because SSO maintains stateful protocol and application information, the user session information is maintained during a switchover. Line cards continue to forward network traffic with no loss of sessions, providing improved network availability.
SSO provides faster switchover by fully initializing and configuring the standby fabric card, and by synchronizing state information, which reduces the time required for routing protocols to converge. The CPT 50 panel that is connected directly to the active fabric card will be disconnected due to SSO.
SSO takes advantage of fabric card redundancy to increase network availability. SSO establishes one of the fabric cards as the active card and the other fabric card is established as the standby card, and then synchronizes critical state information between them. Following an initial synchronization between the two cards, SSO dynamically maintains state information between them.
SSO enables the system to keep all the sessions of HA-aware protocols up during a switchover. This ensures that the services are not affected during switchovers and upgrades.
 Note | Carrier Packet Transport (CPT) supports only the SSO redundancy mode. |
Cisco Nonstop Forwarding (NSF) works with SSO to minimize the network downtime following a switchover. The main objective of NSF is to continue forwarding IP packets following a fabric card switchover.
Prerequisites for SSO
Two fabric cards must be installed on the CPT 200 and CPT 600 shelf.
Restrictions for SSO
General Restrictions
For NSF support, neighboring routers must run NSF-enabled images, though SSO need not be configured on the neighboring device.
Switchover Process Restrictions
If the active fabric card fails before the standby fabric card is ready to switchover, both the fabric cards are reset.
Card Crash During SSO
When the fabric card or line card crashes during SSO, the crash handler shuts down the laser signal on the front ports of the card. The far end detects loss of signal on this path and switches to the protection path if available.
- SSO Synchronization
- Redundancy Modes
- Switchover Operation
- NTP-J17 Manage SSO
- DLP-J46 Perform a Manual Switchover Using CTC
- DLP-J47 Verify SSO Configuration Using Cisco IOS Commands
- DLP-J48 Verify SSO Configuration Using CTC
- Examples of SSO Configuration
- Possible SSO Problem Situations
- DLP-J49 Troubleshoot SSO Using Cisco IOS Commands
- SSO Aware Protocols and Applications
SSO Synchronization
Fabric Card Synchronization
Both the fabric cards must be running the same configuration so that the standby fabric card is always ready to assume control if the active fabric card fails.
To achieve the benefits of SSO, synchronize the configuration information from the active fabric card to the standby fabric card at startup and whenever changes to the active fabric card configuration occur. This synchronization occurs in two separate phases:
When the standby fabric card is booting, the configuration information is synchronized in bulk from the active fabric card to the standby fabric card.
When configuration or state changes occur, an incremental synchronization is conducted from the active fabric card to the standby fabric card.
Note | The CPT 50 panels connected to the active fabric card and the active fabric card are reset during the switchover. |
Bulk Synchronization During Initialization
When a system with SSO is initialized, the active fabric card performs a chassis discovery (discovery of the number and type of line cards and fabric cards in the system) and parses the startup configuration file.
The active fabric card then synchronizes this data to the standby fabric card and instructs the standby fabric card to complete its initialization. This method ensures that both fabric cards contain the same configuration information.
Even though the standby fabric card is fully initialized, it interacts only with the active fabric card to receive incremental changes to the configuration files as they occur.
Incremental Synchronization
After both the fabric cards are fully initialized, any further changes to the running configuration or active states are synchronized to the standby fabric card as they occur. Active fabric card states are updated as a result of processing protocol information, external events (such as the interface coming up or down), user configuration commands (using CLI commands or CTC), or other internal events.
Line Card State Synchronization
Changes to the line card states are synchronized to the standby fabric card. Line card state information is initially obtained during bulk synchronization of the standby fabric card. Following bulk synchronization, line card events received at the active fabric card are synchronized to the standby fabric card.
The following line card states apply to line cards during switchover:
Counters and Statistics Synchronization
The various counters and statistics maintained in the active fabric card are reset during a switchover and are not synchronized with the standby fabric card.
Redundancy Modes
CPT supports only the SSO redundancy mode.
SSO Redundancy Mode
In SSO redundancy mode, the standby fabric card is fully initialized. The active fabric card dynamically synchronizes the startup and running configuration changes to the standby fabric card, which means that the standby fabric card need not be reloaded and reinitialized. SSO supports synchronization of line card, protocol, and application state information between the fabric cards.
Switchover Operation
During switchover, the system control and routing protocol execution are transferred from the active fabric card to the standby fabric card.
Switchover Conditions
The following conditions cause a switchover from the active fabric card to the standby fabric card:
The active fabric card fails.
Online removal of the active fabric card automatically forces a stateful switchover to the standby fabric card.
Forced switchover from the active fabric card to the standby fabric card through CTC or CLI.
The reload command causes a switchover from the active fabric card to the standby fabric card.
Keepalive or Heartbeat failure causes a switchover from the active fabric card to the standby fabric card.
The fabric card polls the peer cards at regular intervals to check whether the cards are connected to the system. If the fabric card does not receive a message within a specific duration from its peer card, the fabric card assumes that the peer card is down. The default duration for the fabric card to receive the Keepalive indication message is 9000 milliseconds.
NTP-J17 Manage SSO
| Purpose | This procedure manages SSO configuration. |
| Tools/Equipment | None |
| Prerequisite Procedures | None |
| Required/As Needed | As needed |
| Onsite/Remote | Onsite or remote |
| Security Level | Provisioning or higher |
Stop. You have completed this procedure. |
DLP-J46 Perform a Manual Switchover Using CTC
| Purpose | This procedure performs a manual switchover from the active fabric card to the standby fabric card using CTC. |
| Tools/Equipment | None |
| Prerequisite Procedures | None |
| Required/As Needed | As needed |
| Onsite/Remote | Onsite or remote |
| Security Level | Provisioning or higher |
The fabric card can be in one of the following states during the switchover.
The active fabric card moves to one of the above states after the switchover.
| Step 1 | Complete the NTP-J22 Log into CTC procedure at a node where you want to switchover from the active fabric card to the standby fabric card. |
| Step 2 | From the View menu, choose Go to Home View. |
| Step 3 | Right-click the fabric or line card and choose Open Packet Transport System View. The Packet Transport System View dialog box appears. |
| Step 4 | Click the Maintenance tab. |
| Step 5 | From the left pane, click High-Availability. |
| Step 6 | In the Fabric Cards area, click Switch to perform a manual switchover from the active fabric card to the standby fabric card. |
| Step 7 | Click Apply. |
| Step 8 | Return to your originating procedure (NTP). |
DLP-J47 Verify SSO Configuration Using Cisco IOS Commands
| Purpose | This procedure allows you to verify that SSO is configured using Cisco IOS commands. |
| Tools/Equipment | None |
| Prerequisite Procedures | None |
| Required/As Needed | As needed |
| Onsite/Remote | Onsite or remote |
| Security Level | Provisioning or higher |
DLP-J48 Verify SSO Configuration Using CTC
| Purpose | This procedure verifies SSO configuration using CTC. |
| Tools/Equipment | None |
| Prerequisite Procedures | None |
| Required/As Needed | As needed |
| Onsite/Remote | Onsite or remote |
| Security Level | Provisioning or higher |
| Step 1 | Complete the NTP-J22 Log into CTC procedure at a node where you want to verify the SSO configuration. |
| Step 2 | From the View menu, choose Go to Home View. |
| Step 3 | Right-click the fabric or line card and choose Open Packet Transport System View. The Packet Transport System View dialog box appears. |
| Step 4 | Click the Maintenance tab. |
| Step 5 | From the left pane, click IOS. |
| Step 6 | Click Open IOS Connection. The IOS Login dialog box appears. |
| Step 7 | Enter the user name and password. |
| Step 8 | Enter show redundancy command at the prompt. |
| Step 9 | Press Enter. The output is displayed. The redundant system information, current processor, and peer processor information appears in the output area. The configured redundancy mode is SSO if an entry in the output reads as Configured Redundancy Mode = SSO. |
| Step 10 | Return to your originating procedure (NTP). |
Examples of SSO Configuration
Verify that SSO Is Configured
The following examples verify that SSO is configured on the device.
Router# show redundancy
Redundant System Information :
------------------------------
Available system uptime = 18 hours, 44 minutes
Switchovers system experienced = 1
Standby failures = 0
Last switchover reason = active unit failed
Hardware Mode = Duplex
Configured Redundancy Mode = SSO
Operating Redundancy Mode = SSO
Maintenance Mode = Disabled
Communications = Up
Current Processor Information :
-------------------------------
Active Location = slot 5
Current Software state = ACTIVE
Uptime in current state = 10 minutes
Image Version = Cisco IOS Software, ONS NGXP Software (NGXP-ADVIPSERVICES-M), Experimental Version
15.1(20110216:101154) [ios_ngxp_dev-georgeti-ios_ngxp_dev.pkg 100]
Copyright (c) 1986-2011 by Cisco Systems, Inc.
Compiled Wed 16-Feb-11 16:59 by georgeti
Configuration register = 0x101
Peer Processor Information :
----------------------------
Standby Location = slot 4
Current Software state = STANDBY HOT
Uptime in current state = 8 minutes
Image Version = Cisco IOS Software, ONS NGXP Software (NGXP-ADVIPSERVICES-M), Experimental Version
15.1(20110215:170703) [ios_ngxp_dev-sathk-ngxp_Feb16th 109]
Copyright (c) 1986-2011 by Cisco Systems, Inc.
Compiled Wed 16-Feb-11 15:12 by sathk
Configuration register = 0x101 (will be 0x8001 at next reload)
Router# show redundancy states
my state = 13 -ACTIVE
peer state = 8 -STANDBY HOT
Mode = Duplex
Unit ID = 4
Redundancy Mode (Operational) = SSO
Redundancy Mode (Configured) = SSO
Redundancy State = SSO
Manual Swact = enabled
Communications = Up
client count = 47
client_notification_TMR = 30000 milliseconds
keep_alive TMR = 9000 milliseconds
keep_alive count = 0
keep_alive threshold = 10
RF debug mask = 0x0
Router# show redundancy history
00:00:12 client added: Redundancy Mode RF(29) seq=60 00:00:12 client added: IfIndex(139) seq=61 00:00:12 client added: CHKPT RF(25) seq=68 00:00:12 client added: NGXP Platform RF(4500) seq=76 00:00:12 client added: NGXP CardIntf Mgr RF(4505) seq=77 00:00:12 client added: Event Manager(77) seq=84 00:00:12 client added: Network RF Client(22) seq=109 00:00:12 client added: XDR RRP RF Client(71) seq=135 00:00:12 client added: CEF RRP RF Client(24) seq=136 00:00:12 client added: RFS RF(520) seq=157 00:00:12 client added: Config Sync RF client(5) seq=159
Router# show redundancy switchover history
Index Previous Current Switchover Switchover
active active reason time
----- -------- ------- ---------------- --------------------
1 4 5 active unit failed 10:58:11 PDT Wed Jun 7 2000
Verify SSO Protocols and Applications
Enter the show redundancy command with the client keyword to display the list of applications and protocols that have registered as SSO protocols or applications. You can also verify the list of supported line protocols.
Router# show redundancy clients
clientID = 29 group_id = 1 clientSeq = 60 Redundancy Mode RF clientID = 139 group_id = 1 clientSeq = 61 IfIndex clientID = 25 group_id = 1 clientSeq = 68 CHKPT RF clientID = 4500 group_id = 1 clientSeq = 76 NGXP Platform RF clientID = 4505 group_id = 1 clientSeq = 77 NGXP CardIntf Mgr RF clientID = 4504 group_id = 1 clientSeq = 78 NGXP PB Manager clientID = 4501 group_id = 1 clientSeq = 79 NGXP HAL Resource Manager clientID = 4502 group_id = 1 clientSeq = 80 NGXP NMS Manager clientID = 4503 group_id = 1 clientSeq = 81 NGXP Mac Table Management clientID = 77 group_id = 1 clientSeq = 84 Event Manager clientID = 78 group_id = 1 clientSeq = 106 TSPTUN HA clientID = 22 group_id = 1 clientSeq = 109 Network RF Client clientID = 75 group_id = 1 clientSeq = 126 Tableid HA clientID = 71 group_id = 1 clientSeq = 135 XDR RRP RF Client clientID = 24 group_id = 1 clientSeq = 136 CEF RRP RF Client clientID = 146 group_id = 1 clientSeq = 138 BFD RF Client clientID = 402 group_id = 1 clientSeq = 156 TPM RF client clientID = 520 group_id = 1 clientSeq = 157 RFS RF clientID = 5 group_id = 1 clientSeq = 159 Config Sync RF client clientID = 49 group_id = 1 clientSeq = 181 HDLC clientID = 72 group_id = 1 clientSeq = 182 LSD HA Proc clientID = 113 group_id = 1 clientSeq = 183 MFI STATIC HA Proc clientID = 290 group_id = 1 clientSeq = 184 MPLS TP HA clientID = 204 group_id = 1 clientSeq = 188 ETHER INFRA RF clientID = 226 group_id = 1 clientSeq = 196 LACP clientID = 20 group_id = 1 clientSeq = 203 IPROUTING NSF RF client clientID = 34 group_id = 1 clientSeq = 218 SNMP RF Client clientID = 35 group_id = 1 clientSeq = 228 History RF Client clientID = 90 group_id = 1 clientSeq = 240 RSVP HA Services clientID = 54 group_id = 1 clientSeq = 256 SNMP HA RF Client clientID = 73 group_id = 1 clientSeq = 257 LDP HA clientID = 76 group_id = 1 clientSeq = 258 IPRM clientID = 57 group_id = 1 clientSeq = 259 ARP clientID = 83 group_id = 1 clientSeq = 293 AC RF Client clientID = 82 group_id = 1 clientSeq = 294 CCM RF clientID = 84 group_id = 1 clientSeq = 296 AToM manager clientID = 85 group_id = 1 clientSeq = 298 SSM clientID = 280 group_id = 1 clientSeq = 299 ST PW OAM clientID = 212 group_id = 1 clientSeq = 309 REP Protocol clientID = 151 group_id = 1 clientSeq = 322 IP Tunnel RF clientID = 94 group_id = 1 clientSeq = 323 Config Verify RF client clientID = 506 group_id = 1 clientSeq = 327 Igmp Snooping clientID = 3099 group_id = 1 clientSeq = 347 ISSU process clientID = 4005 group_id = 1 clientSeq = 350 ISSU Test Client clientID = 93 group_id = 1 clientSeq = 354 Network RF 2 Client clientID = 141 group_id = 1 clientSeq = 364 DATA DESCRIPTOR RF CLIENT clientID = 4020 group_id = 1 clientSeq = 393 IOS Config ARCHIVE clientID = 4021 group_id = 1 clientSeq = 394 IOS Config ROLLBACK
Possible SSO Problem Situations
This section describes the possible situations in which SSO troubleshooting may be needed.
DLP-J49 Troubleshoot SSO Using Cisco IOS Commands
| Purpose | This procedure allows you to troubleshoot the SSO feature using Cisco IOS commands. |
| Tools/Equipment | None |
| Prerequisite Procedures | None |
| Required/As Needed | As needed |
| Onsite/Remote | Onsite or remote |
| Security Level | Provisioning or higher |
The following commands do not have to be entered in any specific order.
SSO Aware Protocols and Applications
Protocols and applications that support SSO must be HA-aware. A feature or protocol is HA-aware if it maintains, either partially or completely, undisturbed operation through a fabric card switchover. State information for HA-aware protocols and applications is synchronized from the active fabric card to the standby fabric card to achieve stateful switchover for those protocols and applications.
The following protocols and applications are SSO aware:
Active-Active Data Path
Active-Active Data Path (AADP) is supported. AADP refers to the load sharing between the two fabric cards.
The redundant fabric cards run in an active-standby control model. However, both the fabric cards have ports that carry active traffic.
The active and standby fabric cards are used for load balancing the traffic that is received and destined for line cards. With dual fabric cards, the traffic from one line card to the other line card can be up to 40 Gbps. With a single fabric card, the traffic from one line card to the other line card cannot exceed 32 Gbps. However, the traffic between two fabric cards can be up to 32 Gbps for CPT 600 shelf, and up to 40 Gbps for CPT 200 shelf.
AADP provides the following benefits for the CPT System:
Nonstop Forwarding
Cisco Express Forwarding
A key element of NSF is packet forwarding. In Cisco networking devices, packet forwarding is provided by Cisco Express Forwarding (CEF). Cisco Express Forwarding maintains the Forwarding Information Base (FIB), and uses the FIB information that was current at the time of the switchover to continue forwarding packets during a switchover. This feature eliminates downtime during the switchover.
During the normal NSF operation, Cisco Express Forwarding on the active fabric card synchronizes its FIB and adjacency databases with the FIB and adjacency databases on the standby fabric card. On switchover of the active fabric card, the standby fabric card initially has FIB and adjacency databases that are mirror images of those on the active fabric card. The packet forwarding continues after a switchover as soon as the interfaces and a data path are available.
Nonstop Forwarding
Nonstop Forwarding (NSF) works with the Stateful Switch Over (SSO) feature to minimize the amount of time a network is unavailable following a switchover. The main objective of the NSF is to continue forwarding IP packets after the switchover of the active fabric card.
When a networking device restarts, all the routing peers of that device usually detect that the device went down and then came back up. This down-to-up transition results in routing flap, which could spread across multiple routing domains. Routing flaps caused by routing restarts create routing instabilities, which are detrimental to the overall network performance. NSF helps to suppress routing flaps and improves the network stability.
NSF allows for the forwarding of data packets to continue along known routes while the routing protocol information is being restored following a switchover. With NSF, peer networking devices do not experience routing flaps. Data traffic is forwarded through intelligent line cards while the standby fabric card assumes control from the failed active fabric card during a switchover. The ability of line cards to remain up during the switchover and to be kept current with the FIB on the active fabric card is key to NSF operation.
Note | CPT does not support forwarding IP packets in hardware and supports forwarding only in software. |
The following figure illustrates how SSO is typically deployed in service provider networks. In this example, NSF with SSO is primarily at the access layer (edge) of the service provider network. A fault at this point can result in loss of service for enterprise customers requiring access to the service provider network.
Additional levels of availability may be gained by deploying NSF with SSO at other points in the network where a single point of failure exists. The following figure illustrates an optional deployment strategy that applies NSF with SSO at the enterprise network access layer. In this example, each access point in the enterprise network represents another single point of failure in the network design. In the event of a switchover or a planned software upgrade, enterprise customer sessions would continue uninterrupted throughout the network.
Prerequisite for NSF
Benefits of NSF
The NSF feature has the following benefits:
Improved network availability—NSF continues to forward network traffic and application state information so that user session information is maintained after a switchover.
Overall network stability—Network stability may be improved with the reduction in the number of route flaps that had been created when routers in the network failed and lost their routing tables.
Prevents routing flaps—Because the NSF continues to forward network traffic in the event of a switchover, routing flaps are avoided.
No loss of user sessions—User sessions established prior to the switchover are maintained.
NSF Routing
Each protocol depends on Cisco Express Forwarding to continue forwarding packets during switchover while the routing protocols rebuild the Routing Information Base (RIB) tables. After the routing protocols have converged, Cisco Express Forwarding updates the FIB table and removes stale route entries. Cisco Express Forwarding updates the line cards with the new FIB information.
The routing protocols run only on the active fabric card, and they receive routing updates from the neighboring routers. After a switchover, the routing protocols request that the NSF-aware neighboring devices send the state information to help rebuild the routing tables.
Note | During the NSF operation, the routing protocols depend on Cisco Express Forwarding to continue forwarding the packets while the routing protocols rebuild the routing information. |
OSPF Operation
When an OSPF NSF-capable router performs a fabric card switchover, it must perform two tasks to resynchronize its link state database with its OSPF neighbors. Firstly, it must relearn the available OSPF neighbors on the network without causing a reset of the neighbor relationship. Secondly, it must reacquire the contents of the link state database for the network.
After the fabric card switchover, the NSF-capable router sends an OSPF NSF signal to the neighboring NSF-aware devices. The neighboring network devices recognize this signal as a clue that the neighbor relationship with this router must not be reset. As the NSF-capable router receives signals from other routers on the network, it can begin to rebuild its neighbor list.
When neighbor relationships are reestablished, the NSF-capable router begins to resynchronize its database with all of its NSF-aware neighbors. At this point, the routing information is exchanged between the OSPF neighbors. After this exchange is complete, the NSF-capable device uses the routing information to remove stale routers and update the RIB and FIB with the new forwarding information. The OSPF protocols are then fully converged.
Note | The OSPF NSF requires that all the neighboring network devices be NSF-aware. If a NSF-capable router discovers that it has non NSF-aware neighbors on a particular network segment, it will disable NSF capabilities for that segment. Other network segments composed entirely of NSF-capable or NSF-aware routers will continue to provide NSF capabilities. |
NSF Device Modes
Cisco had implemented the proprietary Cisco NSF. The Graceful OSPF Restart feature supports IETF NSF for OSPF processes in multivendor networks. The NSF device modes of operation common to the Cisco and IETF NSF implementations are as follows:
- NTP-J18 Manage NSF
- DLP-J50 Verify Cisco Express Forwarding NSF Using Cisco IOS Commands
- DLP-J51 Configure OSPF for NSF Using Cisco IOS Commands
- DLP-J52 Verify OSPF for NSF Using Cisco IOS Commands
- Examples of the NSF Configuration
- DLP-J53 Troubleshoot NSF Using Cisco IOS Commands
NTP-J18 Manage NSF
| Purpose | This procedure manages NSF configuration. |
| Tools/Equipment | None |
| Prerequisite Procedures | None |
| Required/As Needed | As needed |
| Onsite/Remote | Onsite or remote |
| Security Level | Provisioning or higher |
Stop. You have completed this procedure. |
DLP-J50 Verify Cisco Express Forwarding NSF Using Cisco IOS Commands
| Purpose | This procedure verifies that Cisco Express Forwarding is NSF capable using Cisco IOS commands. |
| Tools/Equipment | None |
| Prerequisite Procedures | None |
| Required/As Needed | As needed |
| Onsite/Remote | Onsite or remote |
| Security Level | Provisioning or higher |
The Cisco Express Forwarding NSF feature operates by default. Configuration of Cisco Express Forwarding NSF is not necessary.
| Command or Action | Purpose |
|---|
DLP-J51 Configure OSPF for NSF Using Cisco IOS Commands
| Purpose | This procedure configures OSPF for NSF using Cisco IOS commands. |
| Tools/Equipment | None |
| Prerequisite Procedures | None |
| Required/As Needed | As needed |
| Onsite/Remote | Onsite or remote |
| Security Level | Provisioning or higher |
DLP-J52 Verify OSPF for NSF Using Cisco IOS Commands
| Purpose | This procedure verifies OSPF for NSF using Cisco IOS commands. |
| Tools/Equipment | None |
| Prerequisite Procedures | None |
| Required/As Needed | As needed |
| Onsite/Remote | Onsite or remote |
| Security Level | Provisioning or higher |
Examples of the NSF Configuration
Verify that Cisco Express Forwarding Is NSF-capable
The following example shows how to verify that Cisco Express Forwarding is NSF-capable.
show cef state
CEF Status:
RP instance
common CEF enabled
IPv4 CEF Status:
CEF enabled/running
dCEF enabled/running
CEF switching enabled/running
universal per-destination load sharing algorithm, id 7E0E20AE
RRP state:
I am standby RRP: no
RF Peer Presence: yes
RF Peer Comm reached: yes
RF Peer Config done: yes
RF Progression blocked: unblocked (blocked for 00:00:00.588)
Redundancy mode: sso(3)
CEF NSF sync: enabled/running
CEF ISSU Status:
FIBHWIDB broker
Slot(s): 3 5 40 (0x10000000028) (grp 0x37003204) - Not ISSU aware.
FIBIDB broker
Slot(s): 3 5 40 (0x10000000028) (grp 0x37003204) - Not ISSU aware.
FIBHWIDB Subblock broker
Slot(s): 3 5 40 (0x10000000028) (grp 0x37003204) - Not ISSU aware.
FIBIDB Subblock broker
Slot(s): 3 5 40 (0x10000000028) (grp 0x37003204) - Not ISSU aware.
Adjacency update
Slot(s): 3 5 40 (0x10000000028) (grp 0x37003204) - Not ISSU aware.
IPv4 table broker
Slot(s): 3 5 40 (0x10000000028) (grp 0x37003204) - Not ISSU aware.
CEF push
Slot(s): 3 5 40 (0x10000000028) (grp 0x37003204) - Not ISSU aware.
Configure OSPF for NSF
The following example shows how to configure OSPF for NSF on a networking device.
Router# configure terminal Router(config)# router ospf 400 Router(config-router)# nsf
Verify OSPF for NSF
To verify OSPF for NSF, check whether the NSF is configured on the SSO enabled networking device. Verify that “nsf” appears in the OSPF configuration of the SSO-enabled device by entering the show running-config command:
Router# show running-config
router ospf 120 log-adjacency-changes nsf network 192.168.20.0 0.0.0.255 area 0 network 192.168.30.0 0.0.0.255 area 1 network 192.168.40.0 0.0.0.255 area 2
Next, use the show ip ospf command to verify that NSF is enabled on the device.
Router# show ip ospf
Routing Process "ospf 1" with ID 192.168.2.1 and Domain ID 0.0.0.1 Supports only single TOS(TOS0) routes Supports opaque LSA SPF schedule delay 5 secs, Hold time between two SPFs 10 secs Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs Number of external LSA 0. Checksum Sum 0x0 Number of opaque AS LSA 0. Checksum Sum 0x0 Number of DCbitless external and opaque AS LSA 0 Number of DoNotAge external and opaque AS LSA 0 Number of areas in this router is 1. 1 normal 0 stub 0 nssa External flood list length 0 Non-Stop Forwarding enabled, last NSF restart 00:02:06 ago (took 44 secs) Area BACKBONE(0) Number of interfaces in this area is 1 (0 loopback) Area has no authentication SPF algorithm executed 3 times
DLP-J53 Troubleshoot NSF Using Cisco IOS Commands
| Purpose | This procedure troubleshoots NSF using Cisco IOS commands. |
| Tools/Equipment | None |
| Prerequisite Procedures | None |
| Required/As Needed | As needed |
| Onsite/Remote | Onsite or remote |
| Security Level | Provisioning or higher |
The following commands do not have to be entered in any specific order.
In-Service Software Upgrade
Software upgrade is an important consideration for high availability. CPT supports the In-Service Software Upgrade (ISSU) process to perform planned software upgrades within the HA system. ISSU provides the ability to perform a stateful upgrade even when both the fabric cards are of different versions. ISSU is built over the SSO infrastructure.
ISSU allows you to perform a software upgrade or downgrade while the system continues to forward packets. In most networks, planned software upgrades are a significant cause of downtime. ISSU takes advantage of the NSF with SSO and eliminates downtime associated with software upgrades by allowing changes while the system remains in service. ISSU lowers the impact that planned maintenance activities have on network service availability; there is less downtime and better access to critical systems.
The software upgrade is always done at the node level and not directly on the CPT cards. When the package is upgraded, CPT cards must also upgrade to the Cisco IOS image present in the new package. Reverting to the earlier version of the software must be done for all the cards in the shelf and not just for CPT cards.
The Transport Node Controller (TNC) card stores the required images in its flash memory and manages the software upgrade process for all the cards.
SSO and ISSU work together to ensure that the states and configuration of the CPT cards are maintained before and after the upgrade.
Note | You can perform the ISSU only using CTC and not using Cisco IOS commands. |
The ISSU message transformations between the active fabric card and the standby fabric card is supported .The ISSU message transformations between the active fabric card and the line card is also supported. All the CPT components support the ISSU message transformations between the active fabric card and the line card except EVC and QoS components.
Prerequisites for ISSU
Restrictions for ISSU
Upgrade Activities in ISSU
The following upgrade activities take place sequentially in a system that has a single fabric card. However, it is recommended that two fabric cards are used in the system.
The TNC card boots with the latest image.
The TNC card sends the upgrade request to the active fabric card.
The active fabric card predownloads its image and the images for the line card.
The active fabric card sends the predownload request sequentially to all the line cards based on the slot ID.
All the line cards predownload their images.
The active fabric card and the line cards reboot with the latest image.
The following upgrade activities take place sequentially in a system that has two fabric cards:
The TNC card boots with the latest image.
The TNC card sends the upgrade request to both the active and standby fabric cards.
The active and standby fabric cards predownload their images and the images for the line card.
The active fabric card sends the predownload request sequentially to all the line cards based on the slot ID.
All the line cards predownload their images.
The active fabric card sends the reboot request to the standby fabric card.
The standby fabric card reboots with the latest image.
When the standby fabric card reaches the hot standby state, the active fabric card reboots.
On upgrade to release 9.5, the new active fabric card reloads all the line cards simultaneously without waiting for the standby fabric card to come up.
When all the line cards are up, the active fabric card clears the Upgrade alarm on the TNC card.
| Source Release | Destination Release | Line Card Reload |
|---|---|---|
| 9.5.x | 9.5.x | All the line cards reload sequentially. |
| 9.5.x | 9.7 | All the line cards reload sequentially. |
| Source Release | Destination Release | Line Card Reload |
|---|---|---|
| 9.7 | 9.5.x | All the line cards reload sequentially. |
| 9.5.x | 9.5.x | All the line cards reload sequentially. |
Approximate ISSU Duration
CPT supports up to 2 fabric cards, 20 CPT 50 panels, and 4 line cards on a CPT 600 shelf.
Total upgrade time = Boot of TNC card with latest image + Fabric and line card image download on the fabric card + (24 * Predownload of line cards) + Boot of the standby fabric card + Boot of the active fabric card + (4 * Boot of line cards)
Total Upgrade time = 3 minutes + 3 minutes + (24 * 30 seconds) + 6 minutes + 6 minutes + (4 * 5 minutes) = 50 minutes
The above upgrade duration is calculated based on average boot delays. The delays due to ROM MONitoring (ROMMON) and Field Programmable Gate Array (FPGA) upgrades are not accounted in this calculation.
Card Crash During ISSU
When the active fabric card crashes during the predownload of the line card, the standby fabric card becomes active and resumes the predownload process. There are two possible scenarios:
ISSU Commands
The following commands display the ISSU status details of a client.
show issu capability
show issu comp-matrix
show issu endpoints
show issu clients
show issu sessions
show issu entities
show issu fsm
show issu negotiated
show issu message
For more information on these commands, see the Cisco CPT Command Reference Guide.
Graceful Restart
LDP graceful restart protects traffic when an LDP session is lost. If an interface that supports a graceful-restart-enabled LDP session fails, MPLS LDP-IGP synchronization is still achieved on the interface while it is protected by graceful restart.
LDP graceful restart must be enabled for LDP to be HA compliant. Graceful restart helps to preserve the MPLS forwarding table entries built by LDP over a SSO.
LDP graceful restart must be enabled before establishing a LDP session. You can configure graceful restart through both CTC and Cisco IOS commands. See DLP-J134 Configure MPLS LDP Graceful Restart Using Cisco IOS Commands and DLP-J135 Configure MPLS LDP Graceful Restart Using CTC for more information.