[mpls-linux-general] Re: your mail

[James R. L. <jl...@mi...>]

On Mon, Nov 19, 2001 at 10:57:11AM -0500, Hanxi Zhang wrote:
> 
> Hello Mr. Leu:
> 
> I'm a beginner of mpls-linux. I posted
> on the mailing list a couple general questions
> which are not answered yet. I wonder if
> you could give me some ideas about
> the following two questions, thank you
> very much.
> 
> 1. mplsadm is a manual tool to setup LSP paths
> right? So does it mean that it takes care of
> the setting up of layer 2 connections such
> as a ATM or FR connection, or just map

It can handle handle all of the setup for ethernet (building all
of the correct structires so the networking stack will ARP for the
MAC address) and for ATM (build the correct ATM structures that represent
a uni-directional VC), but does not work on frame relay yet.  I do not have
a means to test FR, so I never finished development on it.

> a FEC to a layer 2 connection that is already
> on?

I does this as well.  Is places a peice of info in the IPv4 routing entries
tha point to the the outgoing MPLS structures.

> 2. When LSP(s) are setup by mplsadm,
> is there any label request/mapping or
> hello messages between those machines
> running mplsadm? In other words, is mplsadm
> a REAL emulation tool for MPLS?

No.  mplsadm only "programs" the mpls forwarding plan. (you can think of it
like the 'route' command which can setup static routes).  You can create
static LSPs with it. If you many dynamic LSP setup you will need to use a 
signaling protocol like LDP or RSVP-TE ( to keep with my analogy, it like
running OSPF via zebra which give you dynamic route setup). The system calls
used by mplsadm would also used by a MPLS signaling protocol to build an LSP
from the info it learns via signalling. (just as zebra uses that same system
calls to add dynamic routing info as does the 'route' command)

> Hanxi
> 
> 
> 
> 
> ----------------------------------------------------------
> Hanxi Zhang
> Research Engineer
> Broadband and Optical Networking
> Communications Research Center
> 
> Tel: (613)991-2960 Fax: (613)998-2753
> 3701 Carling Ave, Ottawa, ON K2H 8S2
> ----------------------------------------------------------
> 
> 
> 
> 

-- 
James R. Leu