Looking further at show datapath frame output it may that Jumbo frames are not being processed bidirectionally. They are receiving but do not appear to be transmitting.
(lgrc-wac-106-12) # show datapath frame
+----+------+-----------------------------------------------------+
|SUM/| | | |
|CPU | Addr | Description Value |
+----+------+-----------------------------------------------------+
| | [00] | Allocated Frames 7033 |
| | [01] | Max Allocated Frames 13828 |
| | [03] | Unknown Unicast 81298037 |
| | [05] | IP Datagrams Fragmented 194992648 |
| | [10] | IP Reassembled Datagrams 177587560 |
| | [14] | IP Reassembly Failures 11452 |
| | [22] | WIFI Frames Re-Assembled 5549 |
| | [23] | WIFI Re-Assembly Failures 1715 |
| | [24] | WIFI Re-Assembly Dup Frames 42 |
| | [25] | WIFI AMSDU 7794478 |
| | [30] | WIFI AMSDU De-aggregated 17177975 |
| | [32] | Invalid IP headers Received 6220 |
| | [38] | Flood Frames 93687013 |
| | [45] | Station Not Data Ready 870909 |
| | [46] | Station Inactive 61 |
| | [49] | ARP Request Spoofs 277 |
| | [50] | ARP Reply Spoofs 2909 |
| | [57] | IP spoofs 30 |
| | [58] | CP Policed Frames 43107996 |
| | [59] | Seqno request failure 6 |
| | [62] | VOQ retries 285198 |
| | [65] | Jumbo Wi-Fi Frames 13 |
| | [79] | Heartbeats sent to SP 3106 |
| | [81] | POE descriptor freed 754518 |
+----+------+-----------------------------------------------------+
| | [00] | Jumbo recvd 8178404 || | [01] | Jumbo xmits 1 |+----+------+-----------------------------------------------------+
------------------------------
Michael Dickson
Network Engineer
University of Massachusetts Amherst
------------------------------
Original Message:
Sent: Feb 16, 2021 02:14 PM
From: Michael Dickson
Subject: AP mtu discovery frequency
And jumbo is configured on uplink interface:
interface gigabitethernet 0/0/2
description "wsr1-rt_xe-0/0/1"
trusted
trusted vlan 1-4094
ip access-group "protect-l3-interfaces" session
jumbo
switchport mode trunk
switchport trunk allowed vlan 282,339,342,348,903,906,908,910,912-927,929-933,935-936,938-939,941-947,950,953-955,959-960
------------------------------
Michael Dickson
Network Engineer
University of Massachusetts Amherst
Original Message:
Sent: Feb 16, 2021 01:58 PM
From: Michael Dickson
Subject: AP mtu discovery frequency
Thanks Colin. Good to know that AP MTU discovery is typically sent about once every minute!
It does appear Jumbo frames are being processed by the controllers. The impacted buildings are spread across multiple controllers and there are 1500, 1578 and 8986 MTU setting occurring across controllers. Impacted buildings are not confined to a single controller.
(aruba_local2) #show datapath frame | include Jumbo
| | [65] | Jumbo Wi-Fi Frames 24 |
| | [00] | Jumbo recvd 5392670 |
| | [01] | Jumbo xmits 4 |
(lgrc-wac-106-2) #show datapath frame | include Jumbo
| | [65] | Jumbo Wi-Fi Frames 24 |
| | [00] | Jumbo recvd 5392814 |
| | [01] | Jumbo xmits 4 |
------------------------------
Michael Dickson
Network Engineer
University of Massachusetts Amherst
Original Message:
Sent: Feb 12, 2021 03:29 PM
From: Colin Joseph
Subject: AP mtu discovery frequency
It is typically sent once/minute.
You would typically need
- Firewall Jumbo parameter enabled on your controllers in the stateful firewall configuration
- Jumbo frames configured on the interfaces (port channels) of your controller(s)
- Jumbo frames configured on your switches that your APS/controllers plug into
You can type "show datapath frame " on your controller to see if it is processing jumbo frames.
------------------------------
Any opinions expressed here are solely my own and not necessarily that of Hewlett Packard Enterprise or Aruba Networks.
Original Message:
Sent: Feb 12, 2021 01:28 PM
From: Michael Dickson
Subject: AP mtu discovery frequency
Yes we're using show ap bss-table. We have an open TAC case with Aruba and the switch vendor. We started seeing APs sourced from certain buildings start to drop user data with no obvious changes throughout the infra for weeks/months. APs, controllers and AP host switches have uptimes measured in months. Pings still worked but client data typically did not. We determined that mtu was set to default (1500) in a jumbo frame environment after not getting back mtu discovery info. For problem buildings we hard set mtu to 1490 in ap-system profile and it works.
A bss-table dump of all APs reveals APs end up with one of three different mtu values 1500,1578, and 8986. There are many buildings with mtu 1500 that do not have client issues. Some paths may not have jumbo configured throughout - we're still looking at that. It does seem if I hard set mtu in all ap-system profiles it *should* work but why now? What might have changed when mtu was never specified before? That got me thinking about mtu discovery intervals.
Mike
------------------------------
Michael Dickson
Network Engineer
University of Massachusetts Amherst
Original Message:
Sent: Feb 12, 2021 02:56 AM
From: marcel koedijk
Subject: AP mtu discovery frequency
To stop the MTU size discovery you could set a SAP MTU=1500 in the AP System Profile.
------------------------------
Marcel Koedijk | MVP Guru 2021 | ACMP | ACCP | Ekahau ECSE | Not an HPE Employee | Opionions are my own
Original Message:
Sent: Feb 11, 2021 05:45 PM
From: Colin Joseph
Subject: AP mtu discovery frequency
Are you using "show ap bss-table" to determine the MTU?
------------------------------
Any opinions expressed here are solely my own and not necessarily that of Hewlett Packard Enterprise or Aruba Networks.
Original Message:
Sent: Feb 11, 2021 01:25 PM
From: Michael Dickson
Subject: AP mtu discovery frequency
Hi,
I'm wondering if anyone knows what the frequency of AP mtu discovery is for connected AP. Is it just once during initial boot or at some interval?
We're troubleshooting an issue with AP mtu discovery where certain clusters of APs are not getting RT feedback on the 1578 mtu discovery packet being sent and instead selecting the default mtu size of 1500. In addition to many APs correctly getting mtu 1578 we're also seeing APs getting mtu 8986. In some cases APs are on the same edge switch, have same interface config, same ap-model, etc. Just one is 1578 and one is 8986. But when revisiting these APs a day or less later we see the mtu changes, never to 1500 but either 1578 or 8986 for these two APs. AP uptime has not changed. This got us wondering about whether the AP must
Thanks in advance!
Mike
------------------------------
Michael Dickson
Network Engineer
University of Massachusetts Amherst
------------------------------