Gig E on 7200 without G1 or G2

Unanswered Question
Oct 28th, 2009

Hi,

Looking at a gigE card(Copper) for a 7204VXR w/npe400, and looking like the C7200-I/O-GE is my only option - Wanted to confirm max mtu on these? (Looks to be only 1524?)...I need at least 1540mtu

PA-GE with WS-G5483 doesn't appear to be compatible.

Thanks in advance.

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Giuseppe Larosa Thu, 10/29/2009 - 07:47

Hello John,

be aware that in any case performance is far lower then 1000 Mbps even with big packets.

Also if you need an MTU of 1540 you probably wants to use it in an MPLS environment.

Hope to help

Giuseppe

generalcommunic... Thu, 10/29/2009 - 15:54

Thanks Giuseppe - We are not wanting Gig performance, but larger mtu is required.

This is for a redundant 7200(Primary has G2) - It is used as LNS, and over FE the 1500byte MTU causes clients mtu problems, as L2TP tunnel consumes 40byte overhead.

So just want to confirm if the io card has user settable mtu of 1540(Or greater)

Thanks

Giuseppe Larosa Sun, 11/01/2009 - 05:40

Hello Michael,

I could only find the datasheet

http://www.cisco.com/en/US/products/hw/routers/ps341/products_data_sheet09186a0080088724.html

I remember someone in MPLS forum reported C7200 able to increase MTU up to 1600 bytes on PA FE with new IOS version like 12.4(20)T

I will check

see

http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Service%20Providers&topic=MPLS&topicID=.ee8558c&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40^1%40%40.2cd22bdb/10#selected_message

(you may need to copy the whole text to get the correct URL)

I'm not sure if this can apply to GE on I/O controller

Hope to help

Giuseppe

johnelliot6 Sun, 11/08/2009 - 17:49

Thanks Giuseppe.

I have tested this on 7200 w/ G2, running

12.4(24)T1, and am unable to set mtu on FE Int:

#sh ver

Cisco IOS Software, 7200 Software (C7200P-ADVENTERPRISEK9-M), Version 12.4(24)T1, RELEASE SOFTWARE (fc3)

Technical Support: http://www.cisco.com/techsupport

Copyright (c) 1986-2009 by Cisco Systems, Inc.

Compiled Fri 19-Jun-09 21:12 by prod_rel_team

ROM: System Bootstrap, Version 12.4(12.2r)T, RELEASE SOFTWARE (fc1)

BOOTLDR: Cisco IOS Software, 7200 Software (C7200P-KBOOT-M), Version 12.4(4)XD5, RELEASE SOFTWARE (fc1)

ERT01-SYD uptime is 7 minutes

System returned to ROM by reload at 22:05:51 AEST Sat Jul 14 2001

System image file is "disk2:c7200p-adventerprisek9-mz.124-24.T1.bin"

#interface fastEthernet 2/0

(config-if)#mtu 1501

% Interface FastEthernet2/0 does not support user settable mtu.

#do sh int faste2/0

FastEthernet2/0 is up, line protocol is up

Hardware is DEC21140A, address is 0003.e416.7838 (bia 0003.e416.7838)

MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Full-duplex, 100Mb/s, 100BaseTX/FX

(It was suggested that you still receive the error message, but the mtu does change...It doesn't appear to)

Cisco 7200-I/O-GE+E (From details below, appears to only support 1524mtu....can anyone confirm?)

http://www.cisco.com/en/US/docs/ios/12_1t/12_1t5/feature/guide/dtasio.html

Giuseppe Larosa Sun, 11/08/2009 - 23:47

Hello John,

is the FE on a PA 2FE or a PA 1FE?

I may be wrong but I think it can make the difference. PA 2FE should be able to support the greater MTU.

about the link you have provided there is no explicit sentence about max mtu supported.

we can see in the example of sh controller giga0/0 the following line:

>>> idb->lc_ip_turbo_fs=0x604A82B0, ip_routecache=0x1(dfs=0/mdfs=0), max_mtu=1524

i82543_ds=0x627DA094, registers=0x3C100000, curr_intr=0

but this can reflect current settings.

Hope to help

Giuseppe

johnelliot6 Mon, 11/09/2009 - 15:49

Thanks Giuseppe,

PA is only 1FE - I'm pretty sure I have a 2FE somewhere, I'll see if I can locate, and test shortly.

Hoping someone has an I/O-GE that can confirm that they support a larger mtu before I purchase :)

johnelliot6 Mon, 11/09/2009 - 15:56

Hi Giuseppe,

Located Pa 2FE, and no luck with mtu change:

#sh interface fastEthernet 2/1

FastEthernet2/1 is administratively down, line protocol is down

Hardware is AmdFE, address is 0000.0000.0000 (bia 0000.0000.0000)

MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

(config)#interface fastEthernet 2/1

(config-if)#mtu ?

<64-17940> MTU size in bytes

(config-if)#mtu 1501

% Interface FastEthernet2/1 does not support user settable mtu.

sh interface fastEthernet 2/1

FastEthernet2/1 is administratively down, line protocol is down

Hardware is AmdFE, address is 0000.0000.0000 (bia 0000.0000.0000)

MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

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