Thanks, Pete.
I think I'm beginning to get the picture.(routes are bundled under the
same path vector and path attributes , and in withdrawn routes prefix
length and prefixes are used just like unique keys)
But I need more reading on this after my BSCN test in about 10 hours.
Regards,
Jaeheon
On 11 Jan 2001 10:45:06 -0500, [EMAIL PROTECTED] ("Peter Van Oene")
wrote:
>Here is what I think about the wording below. They key thing to remember is that a
>withdrawn message does not need to carry as much information about a routes
>attributes as does an advertisement message. In both cases, a route describes a
>destination and a BGP Next_Hop address along with other attributes including as
>paths/communities/ etc. In the first case, the advertisement, single routes are
>noted with their full information provided such that the receiving peer can properly
>evaluate the route. However, for a withdrawn route, the receiver really only needs
>to know that the route is unreachable and thus, only the smallest piece of
>information which uniquely identifies the route, that being the destination prefix,
>is transmitted. Because withdraw advertisements transmit so little information about
>the route, and because what they do transmit is rather important for route stability,
>they are bundled together when transmitted.
>
>Does that clarify things a bit?
>
>Pete
>
>
>
>*********** REPLY SEPARATOR ***********
>
>On 1/10/2001 at 8:32 PM Jaeheon Yoo wrote:
>
>>Hi, all
>>
>>Now I'm reviewing BGP 4 for the upcoming BSCN test. I'm getting
>>nervous about it.
>>
>>In p.17 of RFC1771, what does "one route" mean? What's the difference
>>between one route and one destination? Or should "route" be replaced
>>with "path" as is used in BSCN book?
>>
>> An UPDATE message can advertise at most one route, which may be
>> described by several path attributes. All path attributes contained
>> in a given UPDATE messages apply to the destinations carried in the
>> Network Layer Reachability Information field of the UPDATE message
>
>
>>But in the next paragraph, "route" is used as "destination".
>>
>> An UPDATE message can list multiple routes to be withdrawn from
>> service. Each such route is identified by its destination
>>(expressed
>> as an IP prefix), which unambiguously identifies the route in the
>> context of the BGP speaker - BGP speaker connection to which it has
>> been previously been advertised.
>>
>>I hope somebody out there will clarify this to me.
>>Thanks in advance.
>>
>>Jaeheon
>>
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>
>
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