|
|
The following sections are provided:
The goal of Redundant Link Manager (RLM) is to primarily provide a virtual link management over multiple IP networks so that the Q.931 signaling protocol and other proprietary protocols can be transported on top of multiple redundant links between the Cisco Signaling Controller (CSC) and the Network Access Server (NAS). In addition to this, RLM opens, maintains, and closes multiple links, manages buffers of queued signaling messages, and monitors whether links are active for link failover and Signaling Controller failover. The user can create more than one IP connection between the CSC and the NAS.
The RLM goes beyond Q.921, because it allows for future use of different upper layers, and more importantly, allows for multiple, redundant paths to be treated as one path by upper layers.
Release 2 Architecture
CSC---Cisco Signaling Controller. A server which interfaces between the NAS and the SS7 signaling network.
COT---Continuity test. Used to test individual DS0 channels via either loopback or tone detection and generation.
DSP---Digital Signal Processor. Many firmware functions of a NAS are performed by DSPs which are generally provisioned as banks of shared resources among all the DS0s. Typical DSP functions include: data modems, voice CODECS, fax modems and CODECs, and low-level signaling (such as CAS/R2).
HDLC---High-Level Data Link Control.
ISP---Internet service provider.
NAS---Network access server. A Cisco platform (or collection of platforms such as an AccessPath system which interfaces between the packet world (for example, the Internet) and the circuit world (for example, the PSTN).
PSTN---Public Switched Telephone Network.
SS7---Signaling System Number 7.
SSP---Service switching point. An element of an SS7-based Intelligent Network which performs call origination, termination, or tandem switching. The combined NAS/CSC system looks like a single SSP to the SS7 network.
STP---Signal transfer point. An element of an SS7-based Intelligent Network which performs routing of the SS7 signaling.
T1---A digital carrier used to transmit a DS-1 formatted digital signal at 1.544 MHz.
TDM---Time-division multiplexing. The transmission scheme employed by all digital circuits in the PSTN.
RLM---Redundant link manager.
UDP---User Datagram Protocol.
VoIP---Voice over IP. The ability to carry normal telephony-style voice over an IP-based Internet with POTS-like functionality, reliability, and voice quality.
The client or server side must support the RLM protocol, which manages those redundant links between the server and client and handles the link and server failover mechanism.
The following hardware platforms support this feature:
We recommend that all access servers use at least two IP interfaces to connect to the primary and alternative IP interfaces of the CSC. Otherwise, the control traffic will be impacted by the data traffic by sharing the same interface for both types of traffic.
None.
The protocol stack is illustrated in the following figure.
| Extended Q.931 | |
|---|---|
Q.921 &&Center&& | |
UDP | |
IP |
Extended Q.931 provides call control and maintenance functions. The Q.931 implementation is based on Cisco's National ISDN-2 (NI2), with custom enhancements. The Signaling Controller appears as one or more signaling points in an SS7 network, and performs interworking between the various SS7 protocols in use worldwide to the extended NI2 protocol used between the Cisco SC2200 and NAS.
Q.921 is used to encapsulate the Q.931 messages. It guarantees the in-sequence transmission of Extended Q.931 messages and provides for retransmission. UDP provides for the connectionless transfer of signaling messages across the subnetworks (LAN or WAN), connecting the access servers to the signaling controller.
Configure the access server interfaces for Redundant Link Manager.
| Step | Command | Purpose |
|---|---|---|
1 | | Enter enable mode. Enter the password. You have entered enable mode when the prompt changes to |
2 | | Enter global configuration mode. You have entered global configuration mode when the prompt changes to |
3 | | Specify the IP address of the first interface. |
4 | | Specify the IP address of the second interface. |
5 | | Specify the RLM group (network access server) that you want to configure using the rlm group global configuration command. |
6 | | Specify the device name. Specify the link addresses and their weighting preferences. |
7 | | Specify the device name. Specify the link addresses and their weighting preferences. |
8 | |
|
Router# show rlm group 1 status RLM Group 1 Status User/Port: RLM_MGR/3000 Link State: Up Last Link Status Reported: Up Next tx TID: 1 Last rx TID: 0 Server Link Group[r1-server]: link [10.1.1.1(Loopback1), 10.1.4.1] = socket[active] link [10.1.1.2(Loopback2), 10.1.4.2] = socket[standby] Server Link Group[r2-server]: link [10.1.1.1(Loopback1), 10.1.5.1] = socket[opening] link [10.1.1.2(Loopback2), 10.1.5.2] = socket[opening]
Note the following:
Router# show isdn status
Global ISDN Switchtype = primary-ni
ISDN Serial1:23 interface
dsl 0, interface ISDN Switchtype = primary-ni :Primary D channel of nfas group 0
Layer 1 Status:
ACTIVE
Layer 2 Status:
TEI = 0, Ces = 1, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED
Layer 3 Status:
0 Active Layer 3 Call(s)
Activated dsl 0 CCBs = 0
ISDN Serial2:23 interface
dsl 1, interface ISDN Switchtype = primary-ni :Group member of nfas group 0
Layer 1 & 2 Status Not Applicable
Layer 3 Status:
0 Active Layer 3 Call(s)
Activated dsl 1 CCBs = 0
Total Allocated ISDN CCBs = 0
Note the following information for Serial 0:23 (the first half of the messages):
The second half of the messages display information for Serial 1:23.
If you are having trouble:
This section documents new or modified commands. All commands below are used under the top level command, rlm group group-number. All other commands used with this feature are documented in the Cisco IOS Release 11.3 command references.
To reset the hardware logic on an interface, use the clear interface command.
clear interface name-tagname-tag | The logic name to identify the server configuration so that multiple entries of server configuration can be entered. |
Privileged EXEC
This command first appeared in Cisco IOS Release 11.3(7).
Router# clear interface loopback 1 Router# 02:48:52: rlm 1: [State_Up, rx ACTIVE_LINK_BROKEN] over link [10.1.1.1(Loopback1), 10.1.4.1] 02:48:52: rlm 1: link [10.1.1.2(Loopback2), 10.1.4.2] requests activation 02:48:52: rlm 1: link [10.1.1.1(Loopback1), 10.1.4.1] is deactivated 02:48:52: rlm 1: link [10.1.1.1(Loopback1), 10.1.4.1] = socket[10.1.1.1, 10.1.4.1] 02:48:52: rlm 1: [State_Recover, rx USER_SOCKET_OPENED] over link [10.1.1.1(Loopback1), 10.1.4.1] for user RLM_MGR 02:48:52: rlm 1: link [10.1.1.1(Loopback1), 10.1.4.1] is opened 02:48:52: rlm 1: link [10.1.1.1(Loopback1), 10.1.5.1] = socket[10.1.1.1, 10.1.5.1] 02:48:52: rlm 1: [State_Recover, rx USER_SOCKET_OPENED] over link [10.1.1.1(Loopback1), 10.1.5.1] for user RLM_MGR 02:48:52: rlm 1: link [10.1.1.1(Loopback1), 10.1.5.1] is opened 02:48:52: rlm 1: [State_Recover, rx START_ACK] over link [10.1.1.2(Loopback2), 10.1.4.2] 02:48:52: rlm 1: link [10.1.1.2(Loopback2), 10.1.4.2] is activated 02:48:52: rlm 1: [State_Up, rx LINK_OPENED] over link [10.1.1.1(Loopback1), 10.1.4.1] Router# show rlm group 1 status RLM Group 1 Status User/Port: RLM_MGR/3000 Link State: Up Last Link Status Reported: Up_Recovered Next tx TID: 4 Last rx TID: 0 Server Link Group[r1-server]: link [10.1.1.1(Loopback1), 10.1.4.1] = socket[standby, 10.1.1.1, 10.1.4.1] link [10.1.1.2(Loopback2), 10.1.4.2] = socket[active, 10.1.1.2, 10.1.4.2] Server Link Group[r2-server]: link [10.1.1.1(Loopback1), 10.1.5.1] = socket[opening, 10.1.1.1, 10.1.5.1] link [10.1.1.2(Loopback2), 10.1.5.2] = socket[opening, 10.1.1.2, 10.1.5.2]
Router# Router# 02:49:52: rlm 1: [State_Up, rx UP_RECOVERED_MIN_TIMEOUT] 02:49:52: rlm 1: link [10.1.1.1(Loopback1), 10.1.4.1] requests activation 02:49:52: rlm 1: [State_Switch, rx SWITCH_ACK] over link [10.1.1.1(Loopback1), 10.1.4.1] 02:49:52: rlm 1: link [10.1.1.2(Loopback2), 10.1.4.2] is deactivated 02:49:52: rlm 1: link [10.1.1.1(Loopback1), 10.1.4.1] is activated
clear rlm group statistics
debug rlm group
interface
link source weight
protocol rlm port
retry keepalive
server
show rlm group statistics
show rlm group status
show rlm group timer
shutdown
timer
To clear all time stamps to zero, use the clear rlm group command.
clear rlm group group-number linkgroup-number | RLM group number (0 to 255). |
Privileged EXEC.
This command first appeared in Cisco IOS Release 11.3(7).
Router# clear rlm group 1 link Router# 02:48:17: rlm 1: [State_Up, rx ACTIVE_LINK_BROKEN] over link [10.1.1.1(Loopback1), 10.1.4.1] 02:48:17: rlm 1: link [10.1.1.2(Loopback2), 10.1.4.2] requests activation 02:48:17: rlm 1: link [10.1.1.1(Loopback1), 10.1.4.1] is deactivated 02:48:17: rlm 1: [State_Recover, rx LINK_BROKEN] over link [10.1.1.2(Loopback2), 10.1.4.2] 02:48:17: rlm 1: link [10.1.1.1(Loopback1), 10.1.4.1] = socket[10.1.1.1, 10.1.4.1] 02:48:17: rlm 1: [State_Recover, rx USER_SOCKET_OPENED] over link [10.1.1.1(Loopback1), 10.1.4.1] for user RLM_MGR 02:48:17: rlm 1: link [10.1.1.1(Loopback1), 10.1.4.1] is opened 02:48:17: rlm 1: link [10.1.1.2(Loopback2), 10.1.4.2] = socket[10.1.1.2, 10.1.4.2] 02:48:17: rlm 1: [State_Recover, rx USER_SOCKET_OPENED] over link [10.1.1.2(Loopback2), 10.1.4.2] for user RLM_MGR 02:48:17: rlm 1: link [10.1.1.2(Loopback2), 10.1.4.2] is opened 02:48:17: rlm 1: link [10.1.1.1(Loopback1), 10.1.5.1] = socket[10.1.1.1, 10.1.5.1] 02:48:17: rlm 1: [State_Recover, rx USER_SOCKET_OPENED] over link [10.1.1.1(Loopback1), 10.1.5.1] for user RLM_MGR 02:48:17: rlm 1: link [10.1.1.1(Loopback1), 10.1.5.1] is opened 02:48:17: rlm 1: link [10.1.1.2(Loopback2), 10.1.5.2] = socket[10.1.1.2, 10.1.5.2] 02:48:17: rlm 1: [State_Recover, rx USER_SOCKET_OPENED] over link [10.1.1.2(Loopback2), 10.1.5.2] for user RLM_MGR 02:48:17: rlm 1: link [10.1.1.2(Loopback2), 10.1.5.2] is opened 02:48:17: rlm 1: [State_Recover, rx LINK_OPENED] over link [10.1.1.1(Loopback1), 10.1.4.1] 02:48:17: rlm 1: link [10.1.1.1(Loopback1), 10.1.4.1] requests activation 02:48:17: rlm 1: [State_Recover, rx LINK_OPENED] over link [10.1.1.2(Loopback2), 10.1.4.2] 02:48:17: rlm 1: [State_Recover, rx START_ACK] over link [10.1.1.1(Loopback1), 10.1.4.1] 02:48:17: rlm 1: link [10.1.1.1(Loopback1), 10.1.4.1] is activated
clear interface
debug rlm group
interface
link source weight
protocol rlm port
retry keepalive
server
show rlm group statistics
show rlm group status
show rlm group timer
shutdown
timer
The IP addresses of the server will be defined under this context. Each server can have multiple entries of IP addresses or aliases. Use the no form of this command to disable this function.
interface name-tagname-tag | The logic name to identify the server configuration so that multiple entries of server configuration can be entered. |
Disabled
Interface configuration
This command first appeared in Cisco IOS Release 11.3(7).
clear rlm group statistics
clear interface
debug rlm group
link source weight
protocol rlm port
retry keepalive
server
show rlm group statistics
show rlm group status
show rlm group timer
shutdown
timer
This command is a preference weighted multiple entries command. Within the same server, the link preference is specified in weighting. Use the no form of this command to disable this function.
link { hostname name | address IP address } source interface weight numberhostname name | If hostname is used, RLM will look up the DNS server periodically for the hostname configured until lookup is successful or the configuration is removed. |
address IP address | IP address of the link. |
source interface | We recommend you use the loopback interface as the source, so that it is independent of the hardware condition. Also, the source interface should be different in every link to avoid falling back to the same routing path. If you intend to use the same routing path for the failover, a single link is sufficient to implement it. |
weight number | The higher the weighting number, the higher priority it gets to become the active link. If all entries have the same weighting, all links will be treated equally. There is no preference among servers according to the assumption that only one server will accept the connection requests at any given time. Otherwise, the preference will extend across all servers. |
Disabled
RLM configuration
This command first appeared in Cisco IOS Release 11.3(7).
clear rlm group statistics
clear interface
debug rlm group
interface
protocol rlm port
retry keepalive
server
show rlm group statistics
show rlm group status
show rlm group timer
shutdown
timer
The port number for the basic RLM connection can be reconfigured for the whole rlm-group. Use the no form of this command to disable this function.
protocol rlm port port#port# | Refer to Table 1 below for the default port numbers. |
| Protocol | Port Number |
|---|---|
RLM | 3000 |
ISDN | Port[RLM]+1 |
3000
RLM configuration
This command first appeared in Cisco IOS Release 11.3(7).
clear rlm group statistics
clear interface
debug rlm group
interface
link source weight
retry keepalive
server
show rlm group statistics
show rlm group status
show rlm group timer
shutdown
timer
RLM allows keepalive failures in consecutive certain amounts of time configured via CLI before it declares the link is down. Use the no form of this command to disable this function.
retry keepalive number-of-timesnumber of times | Number of keepalive failures allowed before the link is declared down, from 1 to 100. |
3
RLM configuration
This command first appeared in Cisco IOS Release 11.3(7).
clear rlm group statistics
clear interface
debug rlm group
interface
link source weight
protocol rlm port
server
show rlm group statistics
show rlm group status
show rlm group timer
shutdown
timer
The IP addresses of the server will be defined under this context. Each server can have multiple entries of IP addresses or aliases. Use the no form of this command to disable this function.
server name-tagname-tag | The logic name to identify the server configuration so that multiple entries of server configuration can be entered. |
Disabled
RLM configuration
This command first appeared in Cisco IOS Release 11.3(7).
clear rlm group statistics
clear interface
debug rlm group
interface
link source weight
protocol rlm port
retry keepalive
show rlm group statistics
show rlm group status
show rlm group timer
shutdown
timer
To display the network latency of the RLM group, use the show rlm group statistics command.
show rlm group group-number statisticsgroup-number | RLM group number (0 to 255). |
Privileged EXEC.
This command first appeared in Cisco IOS Release 11.3(7).
The following is a sample output from the show rlm group group-number statistics command.
Router# show rlm group 1 statistics
RLM Group 1 Statistics
Link_up:
last time occurred at 02:45:48.724, total transition=1
avg=00:00:00.000, max=00:00:00.000, min=00:00:00.000, latest=00:00:00.000
Link_down:
last time occurred at 02:42:33.724, total transition=1
avg=00:03:15.000, max=00:03:15.000, min=00:00:00.000, latest=00:03:15.000
Link_recovered:
last time occurred at 00:00:00.000, success=0(0%), failure=0
avg=0.000s, max=0.000s, min=0.000s, latest=0.000s
Link_switched:
last time occurred at 00:00:00.000, success=0(0%), failure=0
avg=0.000s, max=0.000s, min=0.000s, latest=0.000s
Server_changed:
last time occurred at 00:00:00.000 for totally 0 times
Server Link Group[r1-server]:
Open the link [10.1.1.1(Loopback1), 10.1.4.1]:
last time occurred at 02:43:03.724, success=1(100%), failure=0
avg=162.000s, max=162.000s, min=0.000s, latest=162.000s
Echo over link [10.1.1.1(Loopback1), 10.1.4.1]:
last time occurred at 02:47:15.724, success=91(62%), failure=54
avg=0.000s, max=0.000s, min=0.000s, latest=0.000s
Open the link [10.1.1.2(Loopback2), 10.1.4.2]:
last time occurred at 02:43:03.724, success=1(100%), failure=0
avg=162.000s, max=162.000s, min=0.000s, latest=162.000s
Echo over link [10.1.1.2(Loopback2), 10.1.4.2]:
last time occurred at 02:47:19.724, success=95(63%), failure=54
avg=0.000s, max=0.000s, min=0.000s, latest=0.000s
Server Link Group[r2-server]:
Open the link [10.1.1.1(Loopback1), 10.1.5.1]:
last time occurred at 02:46:06.724, success=0(0%), failure=1
avg=0.000s, max=0.000s, min=0.000s, latest=0.000s
Echo over link [10.1.1.1(Loopback1), 10.1.5.1]:
last time occurred at 02:47:18.724, success=0(0%), failure=85
avg=0.000s, max=0.000s, min=0.000s, latest=0.000s
Open the link [10.1.1.2(Loopback2), 10.1.5.2]:
last time occurred at 02:46:06.724, success=0(0%), failure=1
avg=0.000s, max=0.000s, min=0.000s, latest=0.000s
Echo over link [10.1.1.2(Loopback2), 10.1.5.2]:
last time occurred at 02:47:18.724, success=0(0%), failure=85
avg=0.000s, max=0.000s, min=0.000s, latest=0.000s
Router#
| Field | Description |
|---|---|
Link_up | Statistics collected when RLM group is in link up state. |
total transition | Total number of transitions into a particular RLM group state. |
avg | How long the average time interval lasts. |
max | How long the maximum time interval lasts. |
min | How long the minimum time interval lasts. |
latest | How long the most recent time interval lasts. |
Link_down | Statistics collected when RLM group is in the link down state. |
Link_recovered | Statistics collected when RLM group is in the link recovery state. |
Link_switched | Statistics collected when RLM group is in the link switching state. |
Server_changed | Statistics collected for when and how many times RLM server failover happens. |
Server Link Group[r1-server] | Statistics collected for those signaling links defined under a particular server link group, for example, r1-server. |
Open the link | Statistics collected when a particular signaling link connection is open (broken). |
Echo over link | Statistics collected when a particular signaling link connection is established. |
clear rlm group statistics
clear interface
debug rlm group
interface
link source weight
protocol rlm port
retry keepalive
server
show rlm group status
show rlm group timer
shutdown
timer
To display the status of the RLM group, use the show rlm group status command.
show rlm group group-number statusgroup-number | RLM group number (0 to 255). |
Privileged EXEC.
This command first appeared in Cisco IOS Release 11.3(7).
The following is a sample output from the show rlm group group-number status command.
Router# show rlm group 1 status RLM Group 1 Status User/Port: RLM_MGR/3000 Link State: Up Last Link Status Reported: Up Next tx TID: 1 Last rx TID: 0 Server Link Group[r1-server]: link [10.1.1.1(Loopback1), 10.1.4.1] = socket[active] link [10.1.1.2(Loopback2), 10.1.4.2] = socket[standby] Server Link Group[r2-server]: link [10.1.1.1(Loopback1), 10.1.5.1] = socket[opening] link [10.1.1.2(Loopback2), 10.1.5.2] = socket[opening]
| Field | Description |
|---|---|
User/Port | A list of registerd RLM users and the corresponding port numbers associated with them. |
RLM_MGR | RLM management module. |
Link State | The current RLM group's link state for connecting to the remote end. |
Last Link Status Reported | The most recent link status change is reported to RLM users. |
Next tx TID | The next transaction ID for transmission. |
Last rx TID | The most recent transaction ID has been received. |
Server Link Group[r1-server] | The status of all signaling links configured under a particular RLM server link group r1-server. |
socket | The status of the individual signaling link. |
Server Link Group[r2-server] | The status of all signaling links configured under a particular RLM server link group (r2-server). |
clear rlm group statistics
clear interface
debug rlm group
interface
link source weight
protocol rlm port
retry keepalive
server
show rlm group statistics
show rlm group timer
shutdown
timer
To display the current timer values, use the show rlm group timer command.
show rlm group group-number timergroup-number | RLM group number (0 to 255). |
Privileged EXEC.
This command first appeared in Cisco IOS Release 11.3(7).
The following is a sample output from the show rlm group group-number timer command.
Router# show rlm group 1 timer RLM Group 1 Timer Values open_wait = 3s force-down = 30s recovery = 12s switch-link = 5s minimum-up = 60s retransmit = 1s keepalive = 1s Router#
| Field | Description |
|---|---|
open_wait | Wait for the connection request to be acked. |
recovery | Time to allow the link to recover to backup link before declaring the link is down. |
minimum-up | Minimum time to force RLM to stay in the down state to make sure the remote end detects the link state is down. |
keepalive | A keepalive packet will be sent out from NAS to CSC periodically. |
force-down | Minimum time to force RLM to stay in down state to make sure the remote end detects the link state is down |
switch-link | The maximum transition period allows RLM to switch from a lower preference link to a higher preference link. If the switching link does not complete successfully before this timer expires, RLM will go into the recovery state. |
retransmit | Because RLM is operating under UDP, it needs to retransmit the control packet if the packet is not acknowledged within this retransmit interval. |
clear rlm group statistics
clear interface
debug rlm group
interface
link source weight
protocol rlm port
retry keepalive
server
show rlm group statistics
show rlm group status
shutdown
timer
To shut down all of the links under the RLM group, use the shutdown command. RLM will not try to reestablish those links until the command is negated. Use the no form of this command to disable this function.
shutdownThis command has no keywords or arguments.
Disabled
RLM configuration
This command first appeared in Cisco IOS Release 11.3(7).
clear rlm group statistics
clear interface
debug rlm group
interface
link source weight
protocol rlm port
retry keepalive
server
show rlm group statistics
show rlm group status
show rlm group timer
timer
These options can overwrite the default setting of timeout values. The defaults are specified in Table 7 and Table 8. Use the no form of this command to disable this function.
timer {force-down | keepalive | minimum-up | open-wait | recovery | retransmit | switch-link} time in secondsforce-down | After RLM enters the down state, RLM will stay in the down state for a certain amount of time to make sure that the remote end will also enter the down state. After this occurs, both can be forced to be in sync again. This timer can also prevent RLM links from going up and down rapidly in an unstable network environment. |
keepalive | A keepalive packet will be sent out from NAS to CSC periodically. |
minimum-up | After a link is recovered from the failure state and RLM is in the up state, RLM will wait for a minimum time to make sure the new recovered link is stabilized before doing any operation. |
open-wait | To overcome the latency while opening several links at the same time, RLM will use this timer to wait before opening the new links, and then choose the link with the highest weighting to become the active signaling link. |
recovery | When NAS loses the active connection to CSC, it will try to reestablish the connection within the interval specified by this command. If it fails to reestablish the connection, RLM will declare that the RLM signaling link is down. |
retransmit | Because RLM is operating under UDP, it needs to retransmit the control packet if the packet is not acknowledged within this retransmit interval. |
switch-link | The maximum transition period allows RLM to switch from a lower preference link to a higher preference link. If the switching link does not complete successfully before this timer expires, RLM will go into the recovery state. |
Disabled
RLM configuration
This command first appeared in Cisco IOS Release 11.3(7).
clear rlm group statistics
clear interface
debug rlm group
interface
link source weight
protocol rlm port
retry keepalive
server
show rlm group statistics
show rlm group status
show rlm group timer
shutdown
Use the debug rlm group group-number command to display RLM errors. Use the no form of this command to disable debugging output.
debug rlm groupgroup-number { packet echo | event }group-number | RLM group number (0 to 255) |
packet echo | Monitors the RLM keepalive on a link. |
event | Monitors RLM state changes. |
This command first appeared in Cisco IOS Release 11.3(7).
Figure 2 shows sample debug rlm group 1 packet echo output.
Router# debug rlm group 1 packet echo 10:07:44: rlm 1: link [1.14.33.34(Ethernet0), 1.14.33.62] rx ECHO_ACK(tid=35167) 10:07:45: rlm 1: link [1.14.33.34(Ethernet0), 1.14.33.62] tx ECHO_REQ(tid=35168) 10:07:45: rlm 1: link [1.14.33.34(Ethernet0), 1.14.33.62] rx ECHO_ACK(tid=35168) 10:07:46: rlm 1: link [1.14.33.34(Ethernet0), 1.14.33.62] tx ECHO_REQ(tid=35169) 10:07:46: rlm 1: link [1.14.33.34(Ethernet0), 1.14.33.62] rx ECHO_ACK(tid=35169) 10:07:47: rlm 1: link [1.14.33.34(Ethernet0), 1.14.33.62] tx ECHO_REQ(tid=35170) 10:07:47: rlm 1: link [1.14.33.34(Ethernet0), 1.14.33.62] rx ECHO_ACK(tid=35170) 10:07:48: rlm 1: link [1.14.33.34(Ethernet0), 1.14.33.62] tx ECHO_REQ(tid=35171) 10:07:48: rlm 1: link [1.14.33.34(Ethernet0), 1.14.33.62] rx ECHO_ACK(tid=35171) 10:07:49: rlm 1: link [1.14.33.34(Ethernet0), 1.14.33.62] tx ECHO_REQ(tid=35172) 10:07:49: rlm 1: link [1.14.33.34(Ethernet0), 1.14.33.62] rx ECHO_ACK(tid=35172)
Table 5 describes the significant fields in Figure 2.
| Field | Description |
|---|---|
10:07:44 | Enabled debug time stamp in hours:minutes:seconds. |
rlm 1 | RLM group number. |
rx | Receive an RLM control packet. |
ECHO_ACK | The RLM ECHO_ACK packet. |
tx | Transmit an RLM control packet. |
ECHO_REQ | The RLM ECHO_REQ packet. |
Figure 3 shows sample debug rlm event output.
Router# debug rlm group 1 event 10:09:55: rlm 1: [State_Up, rx ACTIVE_LINK_BROKEN] over link [1.14.33.34(Ethernet0), 1.14.33.62] 10:09:58: rlm 1: [State_Recover, rx OPEN_WAIT_TIMEOUT] 10:10:01: rlm 1: [State_Recover, rx OPEN_WAIT_TIMEOUT] 10:10:04: rlm 1: [State_Recover, rx OPEN_WAIT_TIMEOUT] 10:10:07: rlm 1: [State_Recover, rx RECOVERY_TIMEOUT] 10:10:07: rlm 1: link [1.14.33.34(Ethernet0), 1.14.33.62] is deactivated 10:10:28: %ISDN-6-LAYER2DOWN: Layer 2 for Interface ThunderDial, TEI 0 changed to down 10:10:37: rlm 1: [State_Down, rx DOWN_MIN_TIMEOUT] 10:10:37: rlm 1: link [1.14.33.34(Ethernet0), 1.14.33.62] = socket[1.14.33.34, 1.14.33.62] 10:10:37: rlm 1: [State_Down, rx USER_SOCKET_OPENED] over link [1.14.33.34(Ethernet0), 1.14.33.62] for user RLM_MGR 10:10:37: rlm 1: link [1.14.33.34(Ethernet0), 1.14.33.62] is opened 10:10:37: rlm 1: link [1.14.33.34(Ethernet0), 1.14.33.62] = socket[1.14.33.34, 1.14.33.62] 10:10:37: rlm 1: [State_Down, rx USER_SOCKET_OPENED] over link [1.14.33.34(Ethernet0), 1.14.33.62] for user ISDN 10:10:37: rlm 1: [State_Down, rx LINK_OPENED] over link [1.14.33.34(Ethernet0), 1.14.33.62] 10:10:40: rlm 1: [State_Down, rx OPEN_WAIT_TIMEOUT] 10:10:40: rlm 1: link [1.14.33.34(Ethernet0), 1.14.33.62] requests activation 10:10:40: rlm 1: [State_Down, rx START_ACK] over link [1.14.33.34(Ethernet0), 1.14.33.62] 10:10:40: rlm 1: link [1.14.33.34(Ethernet0), 1.14.33.62] is activated 10:10:43: %ISDN-6-LAYER2UP: Layer 2 for Interface, TEI 0 changed to up Router-1#
Table 6 describes the significant fields in Figure 3.
| Field | Description |
|---|---|
10:09:55 | Current time in hours:minutes:seconds. |
rlm 1 | RLM group number. |
1.14.33.34 (Ethernet 0), 1.14.33.62 | A source/destination IP address pair assigned for a signaling link. |
%ISDN-6-LAYER2DOWN | System warning message to show that ISDN layer 2 is down. |
For additional software configuration information, see the following publications:
| Timer | Timer's Default Value in Seconds | Usage |
|---|---|---|
rlm_timer_link_echo | 1 | Keepalive timeout for checking link integrity. |
rlm_timer_link_latency_test | 60 | This periodical timer will be reset whenever an echo is sent. |
rlm_timer_link_open_wait | 3 | Wait for the connection request to be acked. |
rlm_timer_link_recovery | 12 | Time to allow the link to recover to backup link before declaring the link is down. |
rlm_timer_link_switch | 5 | Time to detect the link switch failure. |
rlm_timer_link_down_min | 30 | Minimum time to force RLM to stay in the down state to make sure the remote end detects the link state is down. |
rlm_timer_link_up_recovered_min | 60 | Minimum time to stabilize the newly recovered higher preference link before switching over. |
rlm_timer_cmd_ack | 1 | UDP retransmission timer for each RLM request message before the request is acked. |
| Counter | Default Countdown Value | Usage |
|---|---|---|
rlm_link_echo_retry | 3 | Allow certain number of consecutive echo failures before failover. |
Posted: Mon Mar 8 13:44:26 PST 1999
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