Subject: RE: signaling in draft-kompella-mpls-bundle-04.txt

From: Fong Liaw <[email-masked]>
Date: Tue, 20 Feb 2001 12:08:47 -0800

Hi, Yangquang

>  
>  I don't think this is the reason. For RSVP in GMPLS case, 
>  LIH should be used to
>  identify the signaling control interface, not for logical 
>  links (or component
>  links) in data plane. Remember, in transport network, 
>  signaling are typically
>  out-of-band and non-associated.

Out-of-band or in-band, the fact that the Path needs to
select the link is still there. Consider a regular (non-bundled)
link, if one does not specify (strict) ERO, there is no other object
to select the link in either direction. RSVP-HOP is the mechanism.
IMHO, the IPv4 address in RSVP-HOP selects the control 
interface, and LIH selects the individual link.
 
BTW, this (which object to use) is a minor point. As my reply 
to Adrian, the bi-directionality of link (bundled or non-bundled) 
is my real question.

Regards,
-Fong

>  Yangguang

---

From: Yangguang Xu <[email-masked]>
Date: Tue, 20 Feb 2001 16:51:21 -0500

Fong,

My point is LIH is not the right place to put interface ID or Port ID. LIH
should be used to specify control plane signaling interface ID NOT data plane
transport interface ID. 

As for the port ID/or component_interface_ID, it should be part of a Label. The
definition of label in current GMPLS-Signaling functional spec. is incomplete. A
label should be associated with a specific switchable data flow (my definition).
Port ID + channel ID together form a meaningful unit. Separating them into two
objects is not necessary. The procedure is that (1) source node computes ERO in
logical link/bundle level of granularity (2) Each intermediate node specifies
the exact physical interface (the label) for connection creation according to
ERO and local information

BTW, there seem to be some misunderstanding of bi-directional LSP creation in
transport network. In SONET/SDH transport network, (and also IP, ATM switches)
ports are normally bi-directionally identified (which means one port ID actually
indicates two physical ports, one IN, one OUT). So a label has bidirectionally
itself. If all ports within a network are bi-directionally identified, for a
bi-directional LSP, only one bi-directional label is needed. Upstream label,
from concept to implementation, is a redundancy.

Regards,

Yangguang

---

From: Guangzhi Li <[email-masked]>
Date: Tue, 20 Feb 2001 17:21:33 -0500

Hi,

I agree with Yangguang. There are some confusion between IP networks and transport
networks.
(1) IP network signaling is in-band but most transport signaling is out-band or
out-fiber. For transport network, there is a "separate" signaling network.
(2) IP network LSPs are fundamental uni-directioanl but most transport network LSPs
are bi-directional.
(3) IP network bi-directional LSPs need two labels but most transport network
bi-directional LSPs only need one label. Of course it is due to engineering design
not fundamental requirement.
(4) Careful thinking and design are required if a signaling protocol combines them
together, such as GMPLS ......

-- Guangzhi