|
|
This feature module describes the Frame Relay End-to-End Keepalive feature. It includes information on the benefits of the new feature, supported platforms, related documents, and so forth.
This document includes the following sections:
Frame Relay devices connect with each other through virtual circuits. Each virtual circuit is uniquely identified by a Data Link Connection Identifier (DLCI). In environments in which permanent virtual circuits (PVCs) are used, information regarding added or deleted PVCs and information about availability or unavailability of PVCs is carried through a Local Management Interface (LMI) with the use of status bits.
The Frame Relay switch within the local PVC segment deduces the status of the remote PVC segment through a Network-to-Network interface (NNI) and reports the status to the local router. If local management support within the switch is not end-to-end, the keepalive feature is the only source of information about the remote router. Frame Relay end-to-end keepalives provide status to verify that end-to-end communications are working and that traffic is getting through.
Each PVC connecting any two end devices has two separate keepalive systems. Two are needed because the upstream path may not be the same as the downstream path. One system sends out requests and handles responses to those requests. This system is called the send side. The other system handles and replies to requests from the device at the other end of the PVC. This second system is called the receive side. The send side on one device communicates with the receive side on the other device, and vice versa.
The send side sends out a keepalive request and waits for a reply to its request. If a reply is received before the timer expires, a send side:Frame Relay end-to-end keepalives is recorded. If no reply is received before the timer expires, an error event is recorded. A number of the most recently recorded events are examined. If enough error events are accumulated, the keepalive status of the VC is changed from up to down, or if enough consecutive successful replies are received, the keepalive status of the VC will be changed from down to up. The number of events that will be examined is called the event window.
The receive side is similar to the send side. The receive side waits for requests and send outs replies to those requests. If a request is received before the timer expires, a success event is recorded. If a request is not received, an error event is recorded. If enough error events occur in the event window, the state will be changed from up to down. If enough consecutive success events occur, the state will be changed from down to up.
The Frame Relay End-to-End Keepalive feature can be configured in one of four modes: bidirectional, request, reply, or passive-reply.
Because end-to-end keepalives allow traffic flow in both directions, they can be used to carry control and configuration information from end-to-end. Consistency of information between end hosts is critical in applications such as those relating to prioritized traffic and Voice Over Frame Relay. While SVCs can convey such information within end-to-end signaling messages, PVCs will benefit from a bidirectional communication mechanism.
The Frame Relay End-to-End Keepalive feature works between peer Cisco communications devices. It is derived from the Frame Relay LMI protocol. The key difference is that rather than run over the signaling channel, as is the case with LMI, the End-to-End Keepalive feature runs over individual data channels.
Encapsulation of keepalive packets is proprietary; therefore, the feature is available only on Cisco devices running a softwa release that supports the Frame Relay End-to-End Keepalive feature.
For additional information about configuring Frame Relay, refer to the Cisco IOS Release 12.0 Wide-Area Networking Configuration Guide
No new or modified MIBs are supported by this feature.
For descriptions of supported MIBs and how to use MIBs, see the Cisco MIB web site on CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.
No new or modified RFCs are supported by this feature.
Before configuring or using the Frame Relay End-to-End Keepalive feature, you must complete the following task:
The Frame Relay End-to-End Keepalive feature is configured as one of four modes: bidirectional, request, reply, or passive-reply. Each end of a VC must be configured for this feature to function properly. After the feature has been configured, individual parameters can be modified if necessary.
See the following sections for configuration tasks for the Frame Relay End-to-End Keepalive feature. Each task in the list indicates if the task is optional or required:
You must configure both ends of a VC to send keepalives. If one end is configured as bidirectional, the other end must also be configured as bidirectional. If one end is configured as request, the other end must be configured as reply or passive-reply. If one end is configured as reply or passive-reply, the other end must be configured as request.
| Step | Command | Purpose | ||
|---|---|---|---|---|
| Router(config)#map-class frame-relay map-class-name | Specifies a map class for the VC. | ||
| Router(config-map-class)#frame-relay end-to-end
keepalive mode {bidirectiona | request | reply |
passive-reply}
| Specify the Frame Relay end-to-end keepalive mode. |
The four modes determine the type of keepalive traffice each device sends and responds to:
If necessary, you can modify the default parameter values used by the Frame Relay End-to-End Keepalive feature. Use any of the following map-class configuration commands:
| Command | Purpose |
|---|---|
Router(config-map-class)#frame-relay end-to-end keepalive
error-threshold {send | receive} count
| Modifies the number of errors needed to change the keepalive state from up to down. |
Router(config-map-class)#frame-relay end-to-end keepalive
event-window {send | receive} count
| Modifies the number of recent events to check for errors. |
Router(config-map-class)#frame-relay end-to-end keepalive
success-events {send | receive} count
| Modifies the number of consecutive success events required to change the keepalive state from down to up. |
Router(config-map-class)#frame-relay end-to-end keepalive
timer {send | receive} interval
| Modifies the timer interval. |
Use the following command to monitor the status of the Frame Relay End-to-End Keepalive feature:
| Command | Purpose |
|---|---|
Router#show frame-relay end-to-end keepalive interface | Shows the status of Frame Relay end-to-end keepalive. |
This section provides the following Frame Relay end-to-end keepalive configuration examples:
In the following example, the devices at each end of a VC are configured in bidirectional mode using default values:
! router1 router1(config)#map-class frame-relay vcgrp router1(config-map-class)#frame-relay end-to-end keepalive mode bidirectional ! router2 router2(config)#map-class frame-relay vceek router2(config-map-class)#frame-relay end-to-end keepalive mode bidirectional
In the following example, one device is configured in request mode while the other end of the VC is configured in reply mode:
! router1 router1(config)#map-class frame-relay eek router1(config-map-class)#frame-relay end-to-end keepalive mode request ! router2 router2(config)#map-class frame-relay group_3 router2(config-map-class)#frame-relay end-to-end keepalive mode reply
In the following example, one device is configured in request mode while the other end of the VC is configured in reply mode. The event window, error threshold, and success events values are changed so that the interface will change state less frequently:
! router1 router1(config)#map-class frame-relay eek router1(config-map-class)#frame-relay end-to-end keepalive mode request router1(config-map-class)#frame-relay end-to-end keepalive event-window send 5 router1(config-map-class)#frame-relay end-to-end keepalive error-threshold send 3 router1(config-map-class)#frame-relay end-to-end keepalive success-events send 3 ! router2 router2(config)#map-class frame-relay group_3 router2(config-map-class)#frame-relay end-to-end keepalive mode reply
This section documents new commands. All other commands used with this feature are documented in the Cisco IOS Release 12.0 command reference publications.
In Cisco IOS Release 12.0(1)T or later, you can search and filter the output for show and more commands. This functionality is useful when you need to sort through large amounts of output, or if you want to exclude output that you do not need to see.
To use this functionality, enter a show or more command followed by the "pipe" character (|), one of the keywords begin, include, or exclude, and an expression that you want to search or filter on:
command | {begin | include | exclude} regular-expression
Following is an example of the show atm vc command in which you want the command output to begin with the first line where the expression "PeakRate" appears:
show atm vc | begin PeakRate
For more information on the search and filter functionality, refer to the Cisco IOS Release 12.0(1)T feature module titled CLI String Search.
To modify the keepalive error threshold value, use the frame-relay end-to-end keepalive error-threshold map-class configuration command. Use the no form of this command to reset the error threshold value to its default.
frame-relay end-to-end keepalive error-threshold {send | receive} count
send | The number of send-side errors within the event window that will cause the keepalive status to go from up to down. |
receive | The number of receive-side errors within the event window that will cause the keepalive status to go from up to down. |
count | Number of errors required. The maximum value is 32. |
The default value for both the send and receive error threshold is 2.
Map-class configuration
| Release | Modification |
|---|---|
12.0(5)T | This command was introduced. |
The send-side value can only be configured in bidirectional and request modes. The receive-side value can only be configured in bidirectional and reply modes. See the frame-relay end-to-end keepalive mode command
When you configure the error threshold, you will also want to configure the event window. See the frame-relay end-to-end keepalive event-window command.
The following example shows increasing the receive-side error threshold to 4 and changing the event window to 7:
map-class frame-relay olga frame-relay end-to-end keepalive reply frame-relay end-to-end keepalive error-threshold receive 4 frame-relay end-to-end keepalive event-window receive 7
| Command | Description |
Configures the size of the event window. | |
Configures the Frame Releay end-to-end keepalive mode. | |
Configures how many consecutive Frame Relay end-to-end keepalive success events must occur before the interface status is changed from down to up. | |
Configures Frame Relay end-to-end keepalive timers. | |
map-class frame-relay | Defines a map class. |
Shows status of Frame Relay end-to-end keepalive. |
To modify the keepalive event window value, use the frame-relay end-to-end keepalive event-window map-class configuration command. Use the no form of this command to reset the event window value to its default.
frame-relay end-to-end keepalive event-window {send | receive} size
send | The size of the send-side event window. |
receive | The size of the receive-side event window. |
size | Number of events in the event window. The maximum value is 32. |
The default value for both the send and receive event windows is 3.
Map-class configuration
| Release | Modification |
|---|---|
12.0(5)T | This command was introduced. |
The send-side value can only be configured in bidirectional and request modes. The receive-side value can only be configured in bidirectional and reply modes. See the frame-relay end-to-end keepalive mode command
When you configure the event window, you will also want to configure the error-threshold. See the frame-relay end-to-end keepalive error-threshold command.
The following example shows increasing the receive-side error threshold to 4 and changing the event window to 7:
map-class frame-relay olga frame-relay end-to-end keepalive reply frame-relay end-to-end keepalive error-threshold receive 4 frame-relay end-to-end keepalive event-window receive 7
| Command | Description |
Configures how many Frame Relay end-to-end keepalive errors must occur in the event window before the interface status is changed from up to down. | |
Configures the Frame Releay end-to-end keepalive mode. | |
Configures how many consecutive Frame Relay end-to-end keepalive success events must occur before the interface status is changed from down to up. | |
Configures Frame Relay end-to-end keepalive timers. | |
map-class frame-relay | Defines a map class. |
Shows status of Frame Relay end-to-end keepalive. |
To enable Frame Relay end-to-end keepalives, use the frame-relay end-to-end keepalive mode map-class configuration command. Use the no form of this command to disable Frame Relay end-to-end keepalives.
frame-relay end-to-end keepalive mode {bidirectional | request | reply | passive-reply}
bidirectional | Enables bidirectional mode. |
request | Enables request mode. |
reply | Enables reply mode. |
passive-reply | Enables passive reply mode. |
When a Frame Relay end-to-end keepalive mode is enabled, default values depend on which mode is selected. For the meaning of the parameters, see the frame-relay end-to-end keepalive timer, frame-relay end-to-end keepalive event-window, frame-relay end-to-end keepalive error-threshold, and frame-relay end-to-end keepalive success-events commands.
| Parameter | Send-Side | Receive-Side |
|---|---|---|
Timer | 10 seconds | 15 seconds |
Event Window | 3 | 3 |
Error Threshold | 2 | 2 |
Success Events | 2 | 2 |
| Parameter | Send-Side | Receive-Side |
|---|---|---|
Timer | 10 seconds | no value set |
Event Window | 3 | no value set |
Error Threshold | 2 | no value set |
Success Events | 2 | no value set |
| Parameter | Send-Side | Receive-Side |
|---|---|---|
Timer | no value set | 15 seconds |
Event Window | no value set | 3 |
Error Threshold | no value set | 2 |
Success Events | no value set | 2 |
In passive-reply mode, no values are set.
Map-class configuration
| Release | Modification |
|---|---|
12.0(5)T | This command was introduced. |
The following example configures one end of a VC to send keepalive requests and respond to keepalive requests from the other end of the VC:
map-class frame-relay vcgrp1 frame-relay end-to-end keepalive bidirectional
The following example configures one end of a VC to reply to keepalive requests and to increment its error counter if no keepalive requests are received 30 seconds after the latest request:
map-class frame-relay oro34 frame-relay end-to-end keepalive reply frame-relay end-to-end keepalive timer receive 30
| Command | Description |
Configures how many Frame Relay end-to-end keepalive errors must occur in the event window before the interface status is changed from up to down. | |
Configures the size of the event window. | |
Configures how many consecutive Frame Relay end-to-end keepalive success events must occur before the interface status is changed from down to up. | |
Configures Frame Relay end-to-end keepalive timers. | |
map-class frame-relay | Defines a map class. |
Shows status of Frame Relay end-to-end keepalive. |
To modify the keepalive sucess events value, use the frame-relay end-to-end keepalive sucess-events map-class configuration command. Use the no form of this command to reset the success events value to its default.
frame-relay end-to-end keepalive success-events {send | receive} count
send | The number of consecutive send-side success events required to change the keepalive state from down to up. |
receive | The number of consecutive receive-side success events required to change the keepalive state from down to up. |
count | Number of consecutive success events required. The maximum value is 32. |
The default value for both the send and receive sucess events is 2.
Map-class configuration
| Release | Modification |
|---|---|
12.0(5)T | This command was introduced. |
The send-side value can only be configured in bidirectional and request modes. The receive-side value can only be configured in the bidirectional and reply modes. See the frame-relay end-to-end keepalive mode command
If the success events value is set to a low value at the same time that a low value is set for the error threshold value of the frame-relay end-to-end keepalive error-threshold command, the keepalive state of the VC may flap from state to state.
The following example shows how to increase the success events value:
map-class frame-relay vcgrp4 frame-relay end-to-end keepalive request frame-relay end-to-end keepalive success-events send 4
| Command | Description |
Configures how many Frame Relay end-to-end keepalive errors must occur in the event window before the interface status is changed from up to down. | |
Configures the size of the event window. | |
Configures the Frame Releay end-to-end keepalive mode. | |
Configures Frame Relay end-to-end keepalive timers. | |
map-class frame-relay | Defines a map class. |
Shows status of Frame Relay end-to-end keepalive. |
To modify the keepalive timer value, use the frame-relay end-to-end keepalive timer map-class configuration command. Use the no form of this command to reset the timer value to its default.
frame-relay end-to-end keepalive timer {send | receive} interval
send | How frequently to send a keepalive request. |
receive | How long before the receive-side error counter is incremented if no request is received. |
interval | Time in seconds for the timer to expire. |
The default value for the send timer is 10 seconds. The default value for the receive timer is 15 seconds.
Map-class configuration
| Release | Modification |
|---|---|
12.0(5)T | This command was introduced. |
The send-side value can only be configured in bidirectional and request modes. The receive-side value can only be configured in the bidirectional and reply modes. See the frame-relay end-to-end keepalive mode command
The send-side timer expires if a reply has not been received interval seconds after a request is sent. The receive-side timer expires if a request has not been received interval seconds after the previous request.
The following example shows how to set up one end of a VC to send a keepalive request every 15 seconds and increment the error counter if more than 22 seconds elapse between receiving keepalive responses:
map-class frame-relay vcgrp1 frame-relay end-to-end keepalive bidirectional frame-relay end-to-end keepalive timer send 15 frame-relay end-to-end keepalive timer receive 22
| Command | Description |
Configures how many Frame Relay end-to-end keepalive errors must occur in the event window before the interface status is changed from up to down. | |
Configures the size of the event window. | |
Configures the Frame Releay end-to-end keepalive mode. | |
Configures how many consecutive Frame Relay end-to-end keepalive success events must occur before the interface status is changed from down to up. | |
map-class frame-relay | Defines a map class. |
Shows status of Frame Relay end-to-end keepalive. |
To display statistics about Frame Relay end-to-end keepalive, use the show frame-relay end-to-end keepalive EXEC command.
show frame-relay end-to-end keepalive [interface [DLCI]]
interface | (Optional) Interface to display. |
DLCI | (Optional) DLCI to display. |
If no interface specified, show all interfaces.
EXEC
| Release | Modification |
|---|---|
12.0(5)T | This command was introduced. |
Use this command to display the keepalive status of an interface.
The following example shows output from the show frame-relay end-to-end keepalive command:
Router#show frame-relay end-to-end keepalive interface s1 End-to-end Keepalive Statistics for Interface Serial1 (Frame Relay DTE) DLCI = 100, DLCI USAGE = LOCAL, VC STATUS = STATIC (EEK UP) SEND SIDE STATISTICS Send Sequence Number: 86, Receive Sequence Number: 87 Configured Event Window: 3, Configured Error Threshold: 2 Total Observed Events: 90, Total Observed Errors: 34 Monitored Events: 3, Monitored Errors: 0 Successive Successes: 3, End-to-end VC Status: UP RECEIVE SIDE STATISTICS Send Sequence Number: 88, Receive Sequence Number: 87 Configured Event Window: 3, Configured Error Threshold: 2 Total Observed Events: 90, Total Observed Errors: 33 Monitored Events: 3, Monitored Errors: 0 Successive Successes: 3, End-to-end VC Status: UP
| Command | Description |
Configures how many Frame Relay end-to-end keepalive errors must occur in the event window before the interface status is changed from up to down. | |
Configures the size of the event window. | |
Configures the Frame Releay end-to-end keepalive mode. | |
Configures how many consecutive Frame Relay end-to-end keepalive success events must occur before the interface status is changed from down to up. | |
Configures Frame Relay end-to-end keepalive timers. |
This section documents the new debug command related to the Frame Relay End-to-End Keepalive feature.
To display debug messages for the Frame Relay End-to-End Keepalive feature, use the debug frame-relay end-to-end keepalive command. Use the no form of this command to disable the display of debug messages.
[no] debug frame-relay end-to-end keepalive {events | packets}
events | Displays keepalive events. |
packets | Displays keepalive packets sent and received. |
This command is disabled by default.
| Release | Modification |
|---|---|
12.0(5)T | This command was introduced. |
We recommend that both commands be enabled.
The following examples show typical output from the debug frame-relay end-to-end keepalive packets command. The following example shows output for an outgoing request packet:
EEK (o, Serial0.1 DLCI 200): 1 1 1 3 2 4 3
The seven number fields that follow the colon signify the following:
| Field | Description |
|---|---|
first (example value = 1) | Information Element (IE) type. |
second (example value = 1) | IE length. |
third (example value = 1) | Report ID. 1 = request, 2 = reply. |
fourth (example value = 3) | Next IE type. 3 = LIV ID (Keepalive ID). |
fifth (example value = 2) | IE length. (This IE is a Keepalive IE.) |
sixth (example value = 4) | Send sequence number. |
seventh (example value = 3) | Receive sequence number. |
The next example shows output for an incoming reply packet:
EEK (i, Serial0.1 DLCI 200): 1 1 2 3 2 4 4
The seven number fields that follow the colon signify the following:
| Field | Description |
|---|---|
first (example value = 1) | Information Element (IE) type. |
second (example value = 1) | IE length. |
third (example value = 2) | Report ID. 1 = request, 2 = reply. |
fourth (example value = 3) | Next IE type. 3 = LIV ID (Keepalive ID). |
fifth (example value = 2) | IE length. (This IE is a Keepalive IE.) |
sixth (example value = 4) | Send sequence number. |
seventh (example value = 4) | Receive sequence number. |
The next example shows typical output from the debug frame-relay end-to-end keepalive events command:
EEK SUCCESS (request, Serial0.2 DLCI 400) EEK SUCCESS (reply, Serial0.1 DLCI 200) EEK sender timeout (Serial0.1 DLCI 200)
Posted: Tue Nov 30 13:30:47 PST 1999
Copyright 1989-1999©Cisco Systems Inc.