topic An autocomplete hint doesn't in Network Security

ASA5506-X Jumbo frames?

moz — Tue, 12 Mar 2019 09:25:24 GMT

Hi there!

Does anyone know if ASA5506-X support jumbo (or baby-jumbo) frames? Cisco's literature seems to be rather sparse on the subject with ASA manuals stating something along the lines of "... if you model supports it," without expressly stating what models do actually support it; and am rather apprehensive of spending $$$ for a 5505 upgrade if it doesn't.

Thanks!

I haven't tried it, but I

Philip D'Ath — Fri, 26 May 2017 03:46:20 GMT

I haven't tried it, but I just tried entering the commands and it seems to accept.

(config-if)# mtu outside ?
configure mode commands/options:
 <64-9198> MTU bytes

An autocomplete hint doesn't

moz — Fri, 26 May 2017 10:07:53 GMT

An autocomplete hint doesn't mean it works:

ciscoasa(config)# mtu outside ?

configure mode commands/options:
 <64-9198> MTU bytes
ciscoasa(config)# mtu outside 1508

ERROR: Jumbo frames are not supported on this platform.
 MTU size must be <= 1500.

It's supported for all

Marvin Rhoads — Fri, 26 May 2017 10:14:58 GMT

It's supported for all current models - i.e. 5500-X series but not the legacy end-of-sales 5500 (non-X) models. It is not supported on the 5505.

See the note here:

http://www.cisco.com/c/en/us/td/docs/security/asa/asa84/configuration/guide/asa_84_cli_config/interface_start.html#wp1328869

It's recommended that you run ASA 9.1(6) or later.

Reference:

http://www.cisco.com/c/en/us/td/docs/security/asa/asa-command-reference/I-R/cmdref2/m4.html#pgfId-2124541

It's present in software, but

moz — Fri, 26 May 2017 10:14:59 GMT

It's present in software, but that doesn't mean hardware supports it, unfortunately:

Cisco Adaptive Security Appliance Software Version 9.2(4)20 

<snip>

Hardware: ASA5505, 1024 MB RAM, CPU Geode 500 MHz,

<snip>

results in:

ciscoasa(config)# jumbo?
ERROR: % Unrecognized command
ciscoasa(config)# mtu outside 1508

ERROR: Jumbo frames are not supported on this platform.
 MTU size must be <= 1500.

Hence my asking before spending cash to find out that 5506-X doesn't support it either 🙂

Updated my earlier reply with

Marvin Rhoads — Fri, 26 May 2017 10:18:57 GMT

Updated my earlier reply with clarifying detail...

Thanks for the update- that

moz — Fri, 26 May 2017 10:38:54 GMT

Thanks for the update- that is precisely the droid I was looking for (albeit in the 9.X series documentation).

Unfortunately the list in the link you provided omits 5506-X, with the lowest model being 5512-X.

My guess is that to get jumbo support even on 5512-X, one would still have to buy an ASA-IC-6GE-CU/SFP-X card as the 5500-X Series Datasheet suggests.

I believe that list was

Marvin Rhoads — Fri, 26 May 2017 11:44:45 GMT

believe that list was created prior to the release of the 5506, 5508 and 5516-X.

My home 5506-X has the FTD image but I checked and verified that it supports jumbo frames.

I changed the MTU on my Inside interface and it prompted me to reboot.

After reboot I see the MTU size is now at 9198 bytes.

That's very helpful, thanks!

moz — Fri, 26 May 2017 11:48:53 GMT

That's very helpful, thanks!