Ethernet Switches & Routers

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Contributor
Posts: 40
Registered: ‎01-28-2013

Removed BGP peer carrier now getting "Warning: cannot allocate free cache entry"

I have two CER 2024C setup in VRRP and iBGP between them. CER1 is connected to carrier 1 and the CER2 was connected to carrier 2. We discontinued carrier 2 and had errors reaching some websites, so I disconnected the link between CER1 and CER2. I also removed the BGP neighbor entries for carrier 2, from CER1. Now some websites are still acting slow or not loading. I looked at the logs for CER1 and noticed a lot of "Warning: cannot allocate free cache entry". Looking this up I see where someone recommends contacting Brocade support for info on how to increase the system-max ip-route setting but my system is already at the max (524288).

 

I though this might be due to me disconnecting carrier2 and CER2 and CER1 just not flushing it tables. So tonight I am going to clear all IP routes and reboot the CER1 in hopes that it will re-build the routing tables and not fill up again.

 

If anyone can give me any pointers, I will gladly take them Smiley Happy

 

Thanks.

External Moderator
Posts: 4,907
Registered: ‎02-23-2004

Re: Removed BGP peer carrier now getting "Warning: cannot allocate free cache entry"

@john20

I believe you have to increase the max default value in order to accomodate more entry.

 

what is th eoutput value of

"sh ip cache"

TechHelp24
Contributor
Posts: 40
Registered: ‎01-28-2013

Re: Removed BGP peer carrier now getting "Warning: cannot allocate free cache entry"

Isn't the maximum value for a CER 2024C 524288 (acording to this chart http://www.brocade.com/content/html/en/administration-guide/netiron-05900-adminguide/GUID-1DEA917F-F20F-490B-9FEB-85642280D42A.html)?

 

I did my maintenance tonight, and ran

clear ip route

clear ip cache

reload

 

Now all the sites that were not working before are working.

 

Here is the output:

sh ip cache
Total IP and IPVPN Cache Entry Usage on LPs:
 Module        Host    Network       Free      Total
      1          76     524205          7     524288

External Moderator
Posts: 4,907
Registered: ‎02-23-2004

Re: Removed BGP peer carrier now getting "Warning: cannot allocate free cache entry"

[ Edited ]

you can increase the value as follow

 

system-max ip-cache 800000

 

800k - I believe - is max value supported.

 

wr mem and reload is requiered

 

with "sh default value" you should get the output of current entry allocated, by default is usually 600k

TechHelp24
Contributor
Posts: 40
Registered: ‎01-28-2013

Re: Removed BGP peer carrier now getting "Warning: cannot allocate free cache entry"

Here is my attempt:

 

#system-max ip-cache 800000
Error - Parameter ip-cache should be between 4096 and 524288

 

Now when I run show ip cache, I get:

#show ip cache
Total IP and IPVPN Cache Entry Usage on LPs:
 Module        Host    Network       Free      Total
      1          87     524201          0     524288

 

Then, under show default values, we have:

System Parameters      Default    Maximum    Current    Actual     Bootup     Revertible
mac                      65536      131072     65536      65536      65536      Yes       
vlan                     512        8192       4096       4096       4096       Yes       
spanning-tree            32         128        32         32         32         Yes       
rstp                     32         128        32         32         32         Yes       
ip-arp                   4096       16384      4096       4096       4096       Yes       
ip-cache                 290816     524288     524288     524288     524288     Yes       
ip-route                 290816     524288     524288     524288     524288     Yes       

 

And I am still getting warnings in the logging:

Jul  6 00:16:28:I:Warning: cannot allocate free cache entry
Jul  6 00:15:28:I:Warning: cannot allocate free cache entry

 

I don't understand how there is more need for cache with one carrier peering than with two?

External Moderator
Posts: 4,907
Registered: ‎02-23-2004

Re: Removed BGP peer carrier now getting "Warning: cannot allocate free cache entry"

[ Edited ]

John,

I admit that all sound a bit confused, but I was assist few week ago another customer with exact the same problem. here is a official DOC/workaround from brocade - unfortunately I cannot find anymore - and this doc say ( I'm 99,999% sure ) "default value as 600k" now, to be honest, I'm not sure if this was a example from brocade reported in this DOC (?) or if this is indeed the default value ? in the same workaround brocade suggest to set ip-cache and ip-route to higher value as 800000.

however, the platform at this customer running on R06.0.00, and is probable the value increment is not supported on lower Release.

 

I assume you have a maintenance contract, at this point I would suggest to open a TAC with Brocade, in such case I would appreciate if you update this topic with a solution.

 

just last question please, i note you executed the command:

 

->#system-max ip-cache 800000

 

are you in #config mode ?

 

otherwise the command failed.

 

BTW:, please note you must set the value for both ip-cache and ip-route

TechHelp24
Contributor
Posts: 30
Registered: ‎12-13-2010

Re: Removed BGP peer carrier now getting "Warning: cannot allocate free cache entry"

John,

 

your "show default values" state that your CER 2024C system seems to be a old version (pre "RT"). This old systems aren't able to handle full IPv4 DFZ anymore because they have TCAM only for max 524288 IPv4 prefixes and there is no way to configure a higher value.

 

The newer CER "RT" systems have much more TCAM space and can handle up to 1,5Mio IPv4 prefixes.

 

Gerald

Contributor
Posts: 40
Registered: ‎01-28-2013

Re: Removed BGP peer carrier now getting "Warning: cannot allocate free cache entry"

So, you are saying my hardware is too old to handle full Internet route table?

Contributor
Posts: 30
Registered: ‎12-13-2010

Re: Removed BGP peer carrier now getting "Warning: cannot allocate free cache entry"

[ Edited ]

Yes - if it is an old CER, it can't handle a full IPv4 internet table anymore. Roughfly filtered the IPv4 DFZ contain around 590000 prefixes today and it is stll increasing. We had the same issue some time ago with some older MLX systems with the same TCAM/max prefix limitation.

 

Copy&Paste from an old thread:

 

For CER:
256K IPv4 routes + 128K IPv6
448K IPv4 + 64K IPv6
512K IPv4 + 0 IPv6

For CER-RT:
1.5M IPv4 + 512K IPv6

 

I would say your only quick option to avoid further packet loss is to use an additional default route towards your ISP connection. Of cource you can also try to filter some (unwanted? useles? ...) prefixes to reduce the overall amount but I'am in doubt if this is the way to go. 

 

Gerald

External Moderator
Posts: 4,907
Registered: ‎02-23-2004

Re: Removed BGP peer carrier now getting "Warning: cannot allocate free cache entry"

@gerald.krause

 

thanks for the Info , this is very interesting.

TechHelp24

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