Subject: Difrentiation betenn protocols

From: "Yaron E" <[email-masked]>
Date: Sat, 13 Apr 2002 18:10:48 +0200

Hi all,
I am a bit confused of the major responsibilities of MPLS protocols.
Would it be right to say that:
1. Before LSP is created, we need a IGP routing table based on
OSPF/IS-IS/CSPF (CSPF would be OSPF with some extensions)
2. simple LSPs are created based on LDP (DOD or DOU) via LDP protocol, no
signaling is necessary? (RSVP/CR-LDP)
3. if we want to create a tunnel with administrator constraints, like
explicit path, we would need path signaling like RSVP/CR-LDP?

Am I totally out of the loop here or not? :-)

Thanks,

Yaron

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From: Wushao Wen <[email-masked]>
Date: Sat, 13 Apr 2002 09:05:32 -0700 (PDT)

Please read comments inline.

> OSPF/IS-IS/CSPF (CSPF would be OSPF with some extensions)
Yes. MPLS is mainly a signaling protocols. Of course, it change the next
hop selection mechanism from the traditional IP network. 

> signaling is necessary? (RSVP/CR-LDP)
LDP is a signaling protocols, so are RSVP and CR-LDP. LDP creates LDP via
IP next hop routing table. CR-LDP uses source routing. RSVP is similar as
LDP.

 > 3. if we want to create a tunnel with administrator constraints,
like > explicit path, we would need path signaling like RSVP/CR-LDP?

Yes. Traditional IP routing cannot create an explicit route because the
routing is only based on the destination address. 

Wushao