The MPLS WG Archive

[Ajay Simha <asimha@cisco.com>]

On Sat, 15 Sep 2001, Hemant P. Kelkar wrote:

> Hi,
> Sorry for jumping into the discussion, but I have few points related with
> the traffic trunk.
> Can we use the term "aggregate load" in conjunction with traffic trunk ?
> Secondly, the amount of traffic can vary between two given points either
> at POP or inside the core. How does one speifically defines traffic trunk
> in view of the following :

I would think that the traffic load does vary - hence the term "aggregate".
> #1. Services

A traffic trunk could be 1 service or many right?  For example you could have
voice, data and video flowing from popA to popB over a trunk.  Or you could
break them up into three trunks.

> #2. Connections

I think each connection could be seen as a trunk (without getting religious)

> #3. Flows

Many flows would constitue a trunk (in the real deployment context.  Of course
in voice we have a voice trunk everytime I call you over the phone).

> #4. Lifetime of a switched data path inside the network.


I think it is more of "Traffic" characteristics we are talking about here
rather than what path it takes.

Rather than "interpretting the bible" :-)

" A note on terminology: The concept of MPLS traffic trunks is used
	   extensively in the remainder of this document. According to Li and
   Rekhter [3], a traffic trunk is an aggregation of traffic flows of
   the same class which are placed inside a Label Switched Path.
   Essentially, a traffic trunk is an abstract representation of traffic
   to which specific characteristics can be associated. It is useful to
   view traffic trunks as objects that can be routed; that is, the path
   through which a traffic trunk traverses can be changed. In this
   respect, traffic trunks are similar to virtual circuits in ATM and
   Frame Relay networks.  It is important, however, to emphasize that
   there is a fundamental distinction between a traffic trunk and the
   path, and indeed the LSP, through which it traverses. An LSP is a
   specification of the label switched path through which the traffic
   traverses. In practice, the terms LSP and traffic trunk are often
   used synonymously. Additional characteristics of traffic trunks as
   used in this manuscript are summarized in section 5.0."

RFC 2702.

-ajay

> --
> Regards,
> Hemant
>
> Date: Sat, 15 Sep 2001 09:01:41 -0400 (Eastern Daylight Time)
> From: Ajay Simha <asimha@cisco.com>
> To: Zhu Heqing <zhuheqing@huawei.com>
> Cc: mpls@UU.NET
> Subject: Re: Traffic Trunk?
>
> On Sat, 15 Sep 2001, Zhu Heqing wrote:
>
> > Hi, All:
> >
> > I am eager to know what's really meaning of "traffic trunk".
> > In fact, it has been interpreted in RFC2702.(MPLS TE requirement).
> > But I feel it is too abstract to get the point .
> > What I can understand is to map FECs to LSPs directly.
> > Maybe we can extend the routing protocol to use these LSPs.
> > Can you give me a specific example or more specific description?
>
> I would simply define traffic trunk as aggregate traffic from point A to
> point
> B.
>
>
> For example from Pop A of a service provider network to Pop B you would
> always
> have a "known" load of traffic.  This would be your traffic trunk.
>
> -ajay
> >
> > Thanks in advance.
> >
> > Zhu Heqing, Graduate Student
> > University of Electronic Science and Technology of China.
> >
>
> --
> Ajay Simha
> MPLS Deployment Engineer
> IOS Technology Division
> (919) 392-3141
>
> "Study as if you were to live forever
>  Live as if you were to die tomorrow"
>
>  - Mahatma Gandhi
>
>

-- 
Ajay Simha
MPLS Deployment Engineer
IOS Technology Division
(919) 392-3141

"Study as if you were to live forever
 Live as if you were to die tomorrow"

 - Mahatma Gandhi