The MPLS WG Archive

[Jonathan Sadler <Jonathan.Sadler@tellabs.com>]

However, use of PPP on the Section DCC may cause an interoperability
issue if you have a regenerator in line, and it only supports
CLNP/LAPD.  For that reason, GRE encapsulation (ala the Cisco 15303), or
IP over LAPD (ala RFC 1663?) may be a better approach, until a standards
body puts a stake in the sand.

Another issue not covered is the operational use of IS-IS on this
channel.  As IS-IS is used by SONET terminal/regenerator gear, what is
going to happen to all the CPU and memory constrained ADMs out there
when they start receiving the LSPs with all of the TE and GMPLS TLVs? 
Many are limited to less than 50 nodes and less than 100 links in an
Area -- and the Node/Link TLVs are certainly smaller than the TE/GMPLS
TLVs.

Jonathan Sadler

james.d.carlson@east.sun.com wrote:
> 
> Alex Zinin writes:
> >  A number of companies working in the SONET area already use or are
> >  planning to use DCC for IP control plane [I put MPLS list back ;),
> >  since this question is related to GMPLS and OTN-related work].
> >
> >  There are two types of IP encapsulation on DCC that I know of:
> >  LAP-D and PPP/HDLC. We use the second one in our SONET products.
> >
> >  I think writing up an IETF document describing this would make sense.
> 
> Describing which part?  I think there are at least three separate
> issues here.  One is the control plane issue (specifying the use of IP
> over DCC for carrying control messages), another is the encapsulation
> (for which RFCs 1332, 1661, and 1662 should do fine), and a third is
> having ITU-T specify that PPP is a "legal" option for DCC.
> 
> For the first two issues, I think those are already handled.  It's
> just that third one that might be an issue for some users, and I don't
> think that can be done within an IETF working group.
> 
> If you're suggesting a BCP saying that IP/PPP/HDLC/DCC is a good
> thing, I suppose that's possible, but I don't see what it
> accomplishes.
> 
> --
> James Carlson, Internet Engineering       <james.d.carlson@east.sun.com>
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