[nsp] Too much memory fragmentation on a GSR with 12.0(21)S5

Peter NOBLE pn986 at hotmail.com
Thu Mar 27 18:14:09 EST 2003


I just upgraded one 256M GSR router from 12.0(17)S to 12.0(21)S5 and 
suddenly saw the largest memory block size dropped from previously 90M+ down 
to around 50M. Running it a couple days more the memory went down to as low 
as 18M of largest trunk and the free memory is somewhere in 90M. Talked to 
the TAC and he was saying this is because of a new algorithm for converging 
BGP faster that would use more transient memory and this is normal. He was 
also saying the use of transient memory will be more by the use of 
peer-groups. ( we use this gsr to route reflect a couple of smaller boxes, 
using peer-group of course. ) I am concerned how low the largest memory 
block will go to. Questions:

1. Does anyone of you guys see such an issue from 18S to 21S? ( Cisco was 
claiming the new algorithm came in in 18S or something. )

2. Does it stand route-flaps well. I mean would the largest memory block 
keep decreasing down to a point that there are memloc errors?

3. The TAC also explained memory enhancements in subsequent newer mainline 
releases will improve the largest fragment, but we are too hesistant to go 
for 22, 23 or 24S.

4. The TAC said the memory will not be an issue in our case. Why do they 
need to enhance the memory allocation arrangement if there is no problem at 

Thanks all.


MSN 8 helps eliminate e-mail viruses. Get 2 months FREE*. 

More information about the cisco-nsp mailing list