Re: SUA routing contexts

Steve,

Steve Hill wrote:                               (Tue, 19 Jun 2007 14:47:36)
> 
> In IPSP operation it is my understanding that the sending AS and receiving
> AS do not both need to be assigned the same routing context number.  For
> example:
> 
>        AS (rc = 1)
>             |
>            ASP 10.0.0.1:14001
>             *
>             *
>             *
>            ASP 10.0.0.2:14001
>           /   \
> AS (rc = 2)    AS (rc = 3)
> 
> In the above case, the AS at 10.0.0.1 can send messages to both the ASs at
> 10.0.0.2, despite the routing context numbers being different.  As such,
> the routing context parameter in the CLDT message always identifies the
> destination AS, not the source AS.

The above is true only for IPSP DE mode, where the RC represents only a
_single_ direction of traffic flow.  For IPSP SE mode, there can only
be one RC between a pair of (local and remote) AS, representing _both_
directions of traffic flow.

> My question is regarding how the routing context parameter should be used
> when sending to an SG.  The parameter is listed as mandatory, but when
> sending to an SG I am unclear on what value should be placed in the
> parameter since there is no concept of a destination routing context?

The ASP-SG mode is the same as the IPSP SE mode: there can only be one RC
value between an AS and an SGP, again representing _both_ directions of
traffic flow.

This is really no different for SUA than it is for M3UA.

--brian

-- 
Brian F. G. Bidulock
[email protected]
http://www.openss7.org/