Allied Telesis AR700 Series - Manual (Page 48)

Enhancements to BGP Backoff (CR00010160) 48
Version 275-05
C613-10473-00 REV D
Enhancements to BGP Backoff (CR00010160)
The BGP backoff utility allows other processes access to the memory resources they need, without actually shutting BGP down unless it determines that BGP
has backed off for a prolonged period of time.
Upper and Lower Thresholds
This enhancement adds a lower threshold for BGP backoff, which allows BGP to remain backed off until the system memory is much less utilised. To set this
threshold, use the new low parameter in the command:
set bgp backoff[=20..100] [basetime=0..100] [consecutive=0..1000] [low=15..99] [multiplier=1..1000] [step=1..1000]
[totallimit=0..1000]
Together, the backoff and low parameters create upper and lower thresholds which trigger and maintain BGP backoff. When memory usage exceeds the upper
threshold, BGP backoff is triggered. BGP continues to back off until memory usage falls below the lower threshold. At this stage BGP begins processing again,
unless the total or consecutive backoff limits were reached.
Both threshold values represent a percentage of total system memory use. The upper threshold is set using the backoff parameter, and must be a higher
percentage than the lower threshold. The lower threshold is set using the low parameter, and must be a lower percentage than the upper threshold. The backoff
and low parameters cannot be set to the same value.
The default value for the backoff parameter is 95%, while the default value for the low parameter is 90%.
As the router or switch will not allow the backoff parameter value to be set below the low parameter, we recommend that you always adjust these parameters
in the same command. For example:
set bgp backoff=88 low=84
Consecutive Backoffs
If BGP gets to the end of the backoff period and system memory is still above the lower memory use threshold, BGP backs off immediately without performing
any processing. Such backoffs are called consecutive backoffs. The consecutive backoffs default limit is now 5.