The MPLS WG Archive

["Punj, Arun" <Arun.Punj@marconi.com>]

Eric and Matt, 

> -----Original Message-----
> From: Matt Squire [mailto:mattsquire@acm.org]
> Sent: Thursday, July 12, 2001 11:28 AM
> To: erosen@cisco.com
> Cc: George Swallow; Ron Bonica; mpls-list
> Subject: Re: [Fwd: I-D ACTION:draft-pan-lsp-ping-00.txt]
> 
> 
> 
> What prevents a packet with a router alert flag set from 
> being sent over an
> LSP?  I don't recall anything in the specs that specifies 
> router alter packets
> can't be LSP'd.

> Eric Rosen wrote:
> 
> > George> The mechanism is  intentionally tied to the control 
>  plane to ensure
> > George> that the source  is properly informed even if  the 
> reverse data path
> > George> may be broken.
> >
> > If  the reply is  encapsulated in  a UDP  packet which  is 
> addressed  to the
> > tunnel head and has router alert  set, isn't this just as 
> effective, without
> > the dependence on the control plane?
> 

Interesting.. Should it not be in the spec? If not, than
are you not changing the meaning of router alert. If yes,
Eric's solution seems perfectly OK, although it would 
require some sort of additional support on the intermediate
nodes.

Presumably router alert is the reason why the RSVP messages
are finding the way back in reverse direction!!

However, either way, this technique seems to be a hack. The 
right solution is to implement the complete OAM functionaliy
as Neil as pointed out.


Arun Punj
Office of CTO, Marconi Networks,
Ph  : 724-742-7583 - Web: www.marconi.com
1000 Fore Drive, Warrandale, PA - 15086

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