Subject: [lisp] Issue Title (number): MTU and ICMP Filtering(101)

From: Darrel Lewis <[email-masked]>
Date: Tue, 20 Jul 2010 14:51:39 -0700

Issue Title (number): MTU and ICMP Filtering(101)
Draft Section: 5.4.2
Issue Description: Filtering of ICMP messages might be bad.
Comments:

Section 5.4.2

How would this work if the ITR is behind the firewall, and the firewall filters ICMP messages?

Also, in the case where a large volume of traffic has to be moved from one ITR to another (e.g., due to ITR failure), it will take time for the ITR to which the traffic is moved to discover the effective MTU for each locator mapping, and until this occurs, the traffic will be dropped.

Moreover, this ITR could also get overloaded with ICMP Too Big messages, which could further increase the time required to discover the effective MTU for each locator mapping.

Response:

Dear Yakov-

Thank you for your contribution to draft-ietf-lisp-06.txt. The draft authors
have reviewed your comments but do not feel that changes to the document are
warranted at this time.  While this case is possible the authors assume the 
popular use-case will be egress active-active so the map-cache (and 
therefore information about path MTU) is populated in both boxes.  Please 
feel free to continue discussion of your issue on the LISP working group 
mailing list, [email-masked]. Should discussion result in WG consensus 
that changes are required, the authors will incorporate appropriate text 
into a future version of the draft.

	Thanks!
	Darrel, for the LISP document authors