Re: BFD WG adoption for draft-haas-bfd-large-packets

"Albert Fu (BLOOMBERG/ 120 PARK)" <> Fri, 26 October 2018 17:06 UTC

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Date: Fri, 26 Oct 2018 17:06:27 -0000
From: "Albert Fu (BLOOMBERG/ 120 PARK)" <>
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Subject: Re: BFD WG adoption for draft-haas-bfd-large-packets
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Hi Acee,

>> Commenting specifically on the OSPF case, when you have such misconfigured
>> MTUs, this manifests as weird protocol hiccups.B  You don't so much detect
>> that there's an MTU issue - you just see OSPF failing to make progress.
> However, when implementations start supporting ietf-ospf.yang, there?ll be an
> if-config-err notification specifically indicating an MTU-mismatch. ;^) 

As mentioned previously, the issue that we are trying to address is where there's
no issue with OSPF MTU config, but the WAN circuit fails to carry traffic up to
the configured MTU. 

For example, in last 2 weeks, we have 2 such issues, one with major Tier 1
provider in US and another one with Tier 1 provider in Europe, where OSPF was humming 
along fine, the circuits could carry 1500 byte payload but not 1512 byte payload.
This caused intermittent issue to our end user traffic that traversed these links and
not desirable. This is a fault situation - the circuit should not be put
in production. We have redundant circuits and would want to divert traffic from 
these links automatically (hence this draft).