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New Member

Can you configure MTU size for lightweight APs?

Hello,

I have a wireless network using 5508 WLCs and 3600APs. We are seeing a lot of fragmented packets between controllers which are being dropped by firewalls.

Looking at the settings on the APs the default size set for mtu is 1485, meaning by the time capwap & IP headers are added, this goes above he standard 1500bytes when fragmentation is seen.

Is there a way to reduce this via the WLC or AP itself?

FYI:

Global TCP Adjust MSS is set to 1363 which effects TCP traffic... but UDP 

(Cisco Controller) >show ap config general IHPR11_A_AP360_011

Cisco AP Identifier.............................. 0
Cisco AP Name.................................... IHPR11_A_AP360_011
Country code..................................... GB  - United Kingdom
Regulatory Domain allowed by Country............. 802.11bg:-E     802.11a:-E
AP Country code.................................. GB  - United Kingdom
AP Regulatory Domain............................. 802.11bg:-E    802.11a:-E
Switch Port Number .............................. 13
MAC Address...................................... 30:f7:0d:d3:67:27
IP Address Configuration......................... DHCP
IP Address....................................... 10.249.133.245
IP NetMask....................................... 255.255.255.0
Gateway IP Addr.................................. 10.249.133.254
NAT External IP Address.......................... None
CAPWAP Path MTU.................................. 1485  <<<<<<<<<<<<<<<<<<<<<<<<

 

Many thanks

Phil

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Posting

Enable Wireless - Access Points - Global Configuration - Global TCP Adjust MSS

 

[edit]

Oops, didn't read enough of your post.  I see you mention you've already enabled MSS and are asking about UDP.

New Member

yep - UDP specific - already

yep - UDP specific - already adjusted TCP MSS to 1363.

Recommend the discussionhttps

Recommend the discussion

https://supportforums.cisco.com/discussion/10792056/capwap-mtu-and-jumbo-frames

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