Mailing List Archive: BGP: No path is selected as BEST route

BGP: No path is selected as BEST route

Dec 29, 2005, 11:07 AM

Post #1 of 4 (1629 views)

Dear,

After running into a problem with a certain IP not being able to see content in our network, i started to do some testing and I found
that the router doesn't return a path from the BGP table for the destination.

>> SSH at ams-gs-rt1#show ip bgp 82.168.??.??
>> Number of BGP Routes matching display condition : 2
>> Status codes: s suppressed, d damped, h history, * valid, > best, i internal
>> Origin codes: i - IGP, e - EGP, ? - incomplete
>> Network Next Hop Metric LocPrf Weight Path
>> * 82.168.0.0/14 84.233.??.?? 110 0 8928 1299 3257 5615 i
>> * 82.168.0.0/14 217.170.??.?? 90 0 24785 20562 5615 i
>> No path is selected as BEST route

After some google-ing I found this mailinglist with this problem looking a lot like mine.
This was it's awnser:

>> You may want to take a look at the 'show default values' command to make
>> sure you have enough CAM allocated to the routing tables to support all
>> the routes you have. The config command 'system-max ip-route' will
>> allow you to change this, but requires a reboot.

This is my "show version" result:

SW: Version 07.6.06nT53 Copyright (c) 1996-2004 Foundry Networks, Inc.
Compiled on Aug 02 2005 at 16:29:19 labeled as B2P07606n
(2947988 bytes) from Primary B2P07606n.bin
HW: NetIron 400 Router, SYSIF version 21, Serial #: Non-exist
==========================================================================
SL 1: B0GMR4 M4 Management Module, SYSIF 2, M4, ACTIVE
Serial #: CH01013008
8192 KB BRAM, SMC version 1, BM version 21
==========================================================================
SL 2: B24E Copper Switch Module
Serial #: Non-exist
2048 KB BRAM, SMC version 2, BM version 21
256 KB PRAM(256K+0K) and 2048*8 CAM entries for DMA 4, version 0808
256 KB PRAM(256K+0K) and shared CAM entries for DMA 5, version 0808
256 KB PRAM(256K+0K) and shared CAM entries for DMA 6, version 0808
==========================================================================
Active management module:
466 MHz Power PC processor 750 (version 8/8302) 66 MHz bus
512 KB boot flash memory
8192 KB code flash memory
256 KB SRAM
512 MB DRAM
The system uptime is 42 days 2 hours 41 minutes 52 seconds

My question:
Do I need to do a software update in able to fix the routing problem?
(Cause I have never done this before and I prefere testing it a bit more before doing it in a live enviroment)

Kind regards,
Armand Krijgsman

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BGP: No path is selected as BEST route [ In reply to ]

erik at we-dare

Dec 29, 2005, 11:16 AM

Post #2 of 4 (1742 views)

Permalink

Armand,

On Thu, 2005-12-29 at 17:04 +0100, A. Krijgsman - QCC wrote:
> My question:
> Do I need to do a software update in able to fix the routing problem?
> (Cause I have never done this before and I prefere testing it a bit
> more before doing it in a live enviroment)

You really need a "show default value" from config mode and look up the
"ip-route" parameter to see how much routes can be installed. If it's
below the number of routes you're receiving from a single full BGP feed,
chances are you're loosing routes. If you've got enough memory left, you
can increase the value using the "system-max" command, also from config
mode. Check the Foundry docs for more info on the command and possible
parameters. If you do change the value, you'll need to reload the switch
in order for the change to become effective. But before you do, make
sure that the next-hops of the routes are reachable via a direct route
or IGP, since that can also cause routes to not become active.

Cheers,

--
---
Erik Haagsman
Network Architect
We Dare BV
Tel: +31(0)10-7507008
Fax: +31(0)10-7507005
http://www.we-dare.nl

BGP: No path is selected as BEST route [ In reply to ]

a.krijgsman at quality-control-centre

Dec 29, 2005, 11:55 AM

Post #3 of 4 (1620 views)

Permalink

Thanks Erik,

That works for me.
Below exactly what I did:

1. login on router
2. #enable
3. #config terminal
4. (config)# show default value

~~ search for the parameter "ip-route" ~~
(my config it was limited on 140000.)

To upgrade the maximum ip routes to 200000 you need to do the following:

5. (config)# system-max ip-route 200000
6. (config)# write memory
7. (config)# exit
8. #reload

Kind regards,
Armand

----- Original Message -----
From: "Erik Haagsman" <erik@we-dare.net>
To: "A. Krijgsman - QCC" <a.krijgsman at quality-control-centre.net>
Cc: <foundry-nsp at puck.nether.net>
Sent: Thursday, December 29, 2005 4:54 PM
Subject: Re: [f-nsp] BGP: No path is selected as BEST route

> Armand,
>
> On Thu, 2005-12-29 at 17:04 +0100, A. Krijgsman - QCC wrote:
> > My question:
> > Do I need to do a software update in able to fix the routing problem?
> > (Cause I have never done this before and I prefere testing it a bit
> > more before doing it in a live enviroment)
>
> You really need a "show default value" from config mode and look up the
> "ip-route" parameter to see how much routes can be installed. If it's
> below the number of routes you're receiving from a single full BGP feed,
> chances are you're loosing routes. If you've got enough memory left, you
> can increase the value using the "system-max" command, also from config
> mode. Check the Foundry docs for more info on the command and possible
> parameters. If you do change the value, you'll need to reload the switch
> in order for the change to become effective. But before you do, make
> sure that the next-hops of the routes are reachable via a direct route
> or IGP, since that can also cause routes to not become active.
>
> Cheers,
>
> --
> ---
> Erik Haagsman
> Network Architect
> We Dare BV
> Tel: +31(0)10-7507008
> Fax: +31(0)10-7507005
> http://www.we-dare.nl
>
>
>

AW: BGP: No path is selected as BEST route [ In reply to ]

gstammw at gmx

Dec 29, 2005, 12:54 PM

Post #4 of 4 (1628 views)

Permalink

Hello colleagues,

The system-default values are something one doesn't think about when there
are problems.

I'm currently fighting with a problem where vlans and
spanning-tree-instances are limited.
On a B8GMR I can only set no more than 128 spt-instanced and only up to 512
vlans...
vlan 16 512 512
spanning-tree 32 128 128
... But on my J-B2GMR4 I can use many more vlan-instances:
vlan 32 4095 512
spanning-tree 32 128 32

Both routers are using the image B2R07801c.bin and I guess that these values
are somehow limited by the available system an cam-memory.
Is there some sort of guide how many instances one can set depending on the
type of management module and installed memory?

Another thing I've once read somewhere in the documentation is that one can
install a switch-only image on the Bigiron routers. Would this image help in
increasing the spt-instances and vlans? Another idea might be to reduce the
size of ip-routes and ip-cache so that one can increase the other values.
Does anyone of you have a hint for me or maybe the url of the appropriate
document?

Thanks in advance,
Gunther

> -----Urspr?ngliche Nachricht-----
> Von: foundry-nsp-bounces at puck.nether.net
> [mailto:foundry-nsp-bounces at puck.nether.net] Im Auftrag von
> A. Krijgsman - QCC
> Gesendet: Donnerstag, 29. Dezember 2005 17:53
> An: erik at we-dare.net
> Cc: foundry-nsp at puck.nether.net
> Betreff: Re: [f-nsp] BGP: No path is selected as BEST route
>
> Thanks Erik,
>
> That works for me.
> Below exactly what I did:
>
> 1. login on router
> 2. #enable
> 3. #config terminal
> 4. (config)# show default value
>
> ~~ search for the parameter "ip-route" ~~ (my config it was
> limited on 140000.)
>
> To upgrade the maximum ip routes to 200000 you need to do the
> following:
>
> 5. (config)# system-max ip-route 200000
> 6. (config)# write memory
> 7. (config)# exit
> 8. #reload
>
> Kind regards,
> Armand
>
>