Document ID: 17673
Contents
Introduction
Prerequisites
Requirements
Affected Products
Affected Versions
More Information
Related Information
Introduction
Watch out for the SMDS Heartbeat or you might lose your link.
Prerequisites
Requirements
There are no specific requirements for this document.
Affected Products
1200i, 1220i, 1250i, 1270i, 2600i, 2200R, 2220R, 2250R, 2270R, 3500R, VSR-2, and VSR-8
Affected Versions
All versions
More Information
The Heartbeat or polling of an SMDS link is similar to an echo packet. It checks with the far end of the link to ensure it is still there. If the device receives too many missed replies, the link is considered down and starts to drop packets designated for that interface.
Set the polling frequency to 0 in order to keep the link "always up" and not send any polling packets out.
This output shows how to determine whether you should set your PollingFrequency to 0 or not:
SMDSTest>show smds statistics Stats Wan0 Wan1 in 51686 0 out 34106 0 heartbeat in 0 0 heartbeat out 805 0 discard 255 0 BA err 0 0 HE err 0 0 tag err 0 0 IN addr err 0 0 Out Lngth err 0 0 Out Addr err 255 0 Out WAN err 0 0 Ctrl/Data err 0 0 RSRV err 0 0 Encap. err 0 0 Unkwn pkt err 0 0 SMDSTest> config smds wan 0 [ SMDS Wan 0 ]# list [ SMDS Wan 0 ] PollingFrequency = 5 IPmulticast = e186.4403.1273 StationAddress = c186.4403.2108
You can see in this example that the "heartbeat in" is zero. This means that the far end does not send any heartbeat. This example SMDS link has been plagued with intermittant link loss. The culprit is the lack of heartbeat sent from the far end. If you set the PollingFrequency of this router to 0, then it does not care whether the far side sends a heartbeat or not. Be sure that the far side does not depend on your heartbeat because setting it to 0 ceases your sending a heartbeat to the far end.
In this case, you can also check with the far end and have them turn their heartbeat, or polling, on instead of turning this one off.
Related Information
| Updated: May 03, 2004 | Document ID: 17673 |