[CC'ed IS-IS wg too]
Regarding the following discussions at last IETF and the corresponding modified text in http://tools.ietf.org/html/draft-ietf-rtgwg-remote-lfa-04 , regarding the same I have the following question to authors - ======================================================================= - Targeted LDP Address - Advertise in protocol. This is preferred. However, some boxes don't advertise. [Uma]: I think this was mentioned because it's been said non-TE participating/legacy nodes won't advertise this. - Management configuration as a requirement. - Pick an address arbitrarily. Uma: What configuration is expected? Stewart: Could be silent since it is a vendor implementation issue. Hannes: Lowest IP address is useless. A node should be able to advertise that it doesn't support T-LDP. Rob Shakir - Draft should not remain silent on this issue. Stewart: Use Router-ID if not configured to do otherwise like using a different address. The text now says: In the absence of a protocol to learn the preferred IP address for targeted LDP, an LSR should attempt a targeted LDP session with the Router ID [RFC2328] [RFC5305] [RFC5340], unless it is configured otherwise. [Uma]: ..then the above text can be potentially conflicting to what is stated in Section 12 - "To prevent their use as an attack vector the repair tunnel endpoints SHOULD be assigned from a set of addresses that are not reachable from outside the routing domain." If a new private IP address range is provisioned for T-LDP then it may not be possible to indicate the same as RID with multiple loopbacks. I feel the text around this should not be rigid based on this and this is can still present a potential interoperability issue for RLFA.. For IS-IS: This can be addressed by defining auxiliary RIDs TLV (or sub-TLV in TLV 242) specifying the purpose of the RID, in this case for RLFA T-LDP session. With this - a. One need not dip into all reachability prefixes 135/235/236/237 to find the prefix tags b. Also need not get confused if the tag is present because of inter area leaking etc.. We had a small offline discussion on this and welcome others view on this too. -- Uma C.
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