DHCP Option 82 in MPLS VPN

FredZone fredzone at libertysurf.fr
Fri May 25 21:42:45 UTC 2007


I'm not sure that the PE (What is it, PE?) has to know the source VPN of the 
request. Relay agent will intercept the broadcast DHCP request and unicast 
the message to DHCP server(s). When Server(s) replies to the relay agent 
(setted in PE), if it can't determine the VPN destination, it will broadcast 
the DHCP reply (All VPNs will receive the DHCP message and only the DHCP 
client which recognize its own xid will treat the packet).

If Relay Agent Information is activated, it could be used on DHCP replies 
packets to help the relay agent to determine the VPN targeted by the answer 
and forward the answer only on the right one. In this case, that's suppose 
that VPN are seen by PE like Physical Line.

Very interesting case.



----- Original Message ----- 
From: "Aggarwal Vivek-Q4997C" <Q4997C at motorola.com>
To: <dhcp-users at isc.org>
Sent: Wednesday, May 23, 2007 1:04 PM
Subject: DHCP Option 82 in MPLS VPN

> Hi
> There is one scenario
> I want to enable DHCP option 82 in MPLS VPNS
> Two clients belonging to different MPLS VPN's are sending DHCP requests
> over the same VLAN as seen by the relay-agent (assume it is setting on
> the PE) then how will the PE know to which VPN each client and hence the
> associated DHCP request belongs.
> Can anyone please let me know how can I do the above
> Rgds
> Vivek Aggarwal
> -- 
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.467 / Virus Database: 269.7.6/815 - Release Date: 22/05/2007 
> 15:49

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