01-30-2017 10:09 AM - edited 03-05-2019 07:56 AM
Hi All,
Im strugging to find information pertaining to the number of routes allowed on this router / switch.
We use a 4900M as a peering router due to it only being 2u and having plenty port density and not being that expensive.
There are articles online from cisco that mention a 250k route limit as well as a 300k route limit. Is this a TCAM limitation or a software license issue ?
We are running enterprise services but I dont think that matters.
How do we see on the IOS what the limit is and how far its exausted ?
How do I know if thats a bgp table limitation or a ip route limitation ? ie sh ip route or sh ip bgp
As far as I know this is not a normal memory issue ? How do we see TCAM size as far as I understand routes are all in TCAM.
Solved! Go to Solution.
01-30-2017 10:51 AM
Hello,
the 4900M has 512Mb default RAM (fixed) which would approximately coincide with 300K routes. The limiting factor is RAM, and obviously what the CPU can handle.
The IOS will only tell you indirectly whether you are reaching the limit, by looking at the memory and CPU utilization.
01-30-2017 01:06 PM
Hello,
my bad. Apparently the output of that command 'show platform hardware ip route summary' is only available to TAC...
01-30-2017 10:51 AM
Hello,
the 4900M has 512Mb default RAM (fixed) which would approximately coincide with 300K routes. The limiting factor is RAM, and obviously what the CPU can handle.
The IOS will only tell you indirectly whether you are reaching the limit, by looking at the memory and CPU utilization.
01-30-2017 11:02 AM
Hi
It looks like it has 1 gig :
ter-cpt-01#show memory summary
Head Total(b) Used(b) Free(b) Lowest(b) Largest(b)
Processor 146A379C 999671904 328939688 670732216 669141772 670329688
I heard the limiting factor is TCAM and not RAM ?
How do i see the TCAM utilisation ? Is it sh ip route plus sh ip bgp ?
01-30-2017 11:12 AM
Hello,
the 4948E and the 4948E-F have 1Gb of default SDRAM; either way, I think the command to view FIB TCAM utilization on the 4900 is:
show platform hardware ip route summary
01-30-2017 11:20 AM
hi
thanks very much
the output gives me a lot of information that i dont understand at all however this section seems relative please advise ?
entity total used free util%
Entries 258048 98240 159808 38
uRPF Ipv4 0 0 0 0
uRPF Ipv6 0 0 0 0
UC Ipv4 102400 98237 4163 95
MC Ipv4 2048 2 2046 0
UC Ipv6 2048 1 2047 0
MC Ipv6 0 0 0 0
SpecDst 0 0 0 0
SpecSrc 0 0 0 0
unused 151552 151552 0 100
does the total of 258k mean the total routes allowed ?
So the limit is the tcam and not ram correct ?
Is this a hardware limit or a limit cisco put into software to make one upgrade ?
01-30-2017 12:03 PM
Hello,
can you post the output of 'show version' ? I am running the output of the command above through the CLI Analyzer...
01-30-2017 12:11 PM
sure:
ter-cpt-01#sh ver
Cisco IOS Software, Catalyst 4500 L3 Switch Software (cat4500e-ENTSERVICESK9-M), Version 12.2(54)SG, RELEASE SOFTWARE (fc3)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2010 by Cisco Systems, Inc.
Compiled Sun 27-Jun-10 09:28 by prod_rel_team
Image text-base: 0x10000000, data-base: 0x12E09514
ROM: 12.2(44r)SG10
Sushi Revision 11, Tatooine Revision 141, Forerunner Revision 1.78
ter-cpt-01 uptime is 3 weeks, 4 days, 2 hours, 20 minutes
System returned to ROM by power-on
System restarted at 19:45:04 SATIME Thu Jan 5 2017
System image file is "bootflash:/cat4500e-entservicesk9-mz.122-54.SG.bin"
This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.
A summary of U.S. laws governing Cisco cryptographic products may be found at:
http://www.cisco.com/wwl/export/crypto/tool/stqrg.html
If you require further assistance please contact us by sending email to
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cisco WS-C4900M (MPC8548) processor (revision 5) with 1048576K bytes of memory.
Processor board ID JAE17370DJ1
MPC8548 CPU at 1.33GHz, Cisco Catalyst 4900M
Last reset from PowerUp
12 Virtual Ethernet interfaces
32 Gigabit Ethernet interfaces
24 Ten Gigabit Ethernet interfaces
511K bytes of non-volatile configuration memory.
Configuration register is 0x2102
ter-cpt-01#
01-30-2017 01:06 PM
Hello,
my bad. Apparently the output of that command 'show platform hardware ip route summary' is only available to TAC...
02-03-2017 01:03 AM
Hi Georg
THank you your command does work.
Does using soft-reconfigutation use extra tcam memory or normal memory ?
We are running out of tcam is there something we can do ?
02-03-2017 05:23 AM
BGP's soft-reconfig should use RAM. Later BGP implementations shouldn't need to use it.
About the only thing you can do to reduce TCAM usage is to reduce your demand on it. For example, filter your BGP intake to reduce your number of prefixes.
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