Re: [mpls] Ben's Comments on draft-ietf-mpls-sr-over-ip

["Adrian Farrel" <[e-mail]>]

Hey Ben,

>>>   IP Header Fields:  When encapsulating an MPLS packet in UDP, the
>>>      resulting packet is further encapsulated in IP for transmission.
>>>      IPv4 or IPv6 may be used according to the capabilities of the
>>>      network.  The address fields are set as described in Section 2.
>>>
>>> (Does Section 2 say how to set the source address?)
>> 
>> Sure does.
>>       The tunnel selected MUST have its
>>       remote end point (destination) address equal to the address of the
>>       next SR-MPLS capable node along the path (i.e., the egress of the
>>       active node segment).
>
> I might still be missing it.  Is the idea that once you've selected a
> specific tunnel, that naturally will have a record of the source address
> corresponding to that tunnel?  (I only see a literal "remote end point
> (destination) address" in the quoted text, i.e., "source" or "local" do not
> appear.)

Sorry, I completely missed "source" in your question. Stupid of me.

That needs clarifying in the document, you're quite right.
The source address is set to an address of the encapsulating node. 7510 gives further advice when the UDP zero-checksum mode is used. 

This will show up in the next revision.

Best,
Adrian