dyusuf's blog

BGP : Route selection process

Submitted by dyusuf on Sat, 11/01/2008 - 13:25.

Consider only (synchronized) routes with no AS loops and a valid next hop and then:
1. Prefer highest weight - local to router
2. Prefer highest local preference - global within AS
3. Prefer route originated by the local router (next hop=0.0.0.0)
4. Prefer shortest AS path
5. Prefer lowest origin code (IGP  ...  read more »

EIGRP : Stub feature

Submitted by dyusuf on Tue, 08/26/2008 - 02:06.

A stub router sends a special packet info to all neighboring router to report its status as a stub.
Neighboring routers that receives that packet, will not query the stub router for any routes.

Normally, configured in the spoke routers

EIGRP:Query Process

Submitted by dyusuf on Tue, 08/26/2008 - 01:41.

Query process happens with the following:

1.Query is sent when route is lost and NO Feasible Successor is available.
2.The Lost Route is now in active state.
3.Query then sent to all neighboring router on all interface EXCEPT the interface to successor.
4.If the neighbors don't have lost route information, queries are sent to their neighbor.
5.If the router has a alternate route, it answers the query and stop query propagation.

usefull blog link

Submitted by dyusuf on Fri, 08/22/2008 - 10:46.

i read a lot of usefull information from CCIEs or candidates through their blogs. Starting today, i would put any CCIE link on my blog, so anytime i need some info, just go to my blog.

http://blog.internetworkexpert.com/ InternetworkExpert
http://ccie-in-3-months.blogspot.com/ CCIE #19858
http://blog.ioshints.info/ Blog from Ivan Pepelnjak CCIE#1354
http://pwp.netcabo.pt/amsoares/dynamips/dynamips.htm CCIE SP Mini-scenario

NSSA

Submitted by dyusuf on Mon, 08/18/2008 - 10:37.

i got stuck with NSSA behaviour. I might overlook manything. But i got usefull link from discussion groups

www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094a88.sh...

Default Route in NSSA
There are two ways to have a default route in an NSSA. When you configure an area as NSSA, by default the NSSA ABR does not generate a default summary route. In the case of a stub area or an NSSA totally stub area, the NSSA ABR does generate a default summary route.

Default Summary Route  ...  read more »

ospf distance command

Submitted by dyusuf on Tue, 08/12/2008 - 01:36.

usage : filtering routing entering RIB

example distance :

distance 255 150.1.1.1 0.0.0.0 98

where :

255 = metric
150.1.1.1 0.0.0.0 = advertising router
98 = access-list that contain routes to be filtered

georgia and russia

Submitted by dyusuf on Mon, 08/11/2008 - 15:06.

hey.. it is surprising me that people in discussion groups discussing about what happen between Georgia and Russia, and the way US media reporting it..

yes, i am in the stuck state and feel badly sleepy among the followings ---distribution-list, prefix-list, route-map, bla...bla...

whoaaa... if the 5 times CCIE thrown a OOT issue, they will response it. Another privilleges of having multiple CCIE, isn't ??

my suggest : do not watching for the media, staring at their pretty anchor instead ....

route map behaviour

Submitted by dyusuf on Mon, 08/11/2008 - 14:29.

captured from TCP/IP vol 1 Doyle/Caroll...

The behavior of a "deny" action depends on whether the route map is being used for policy routing or for redistribution.
If a route map is being used for redistribution and a route matches a statement with a deny action, the route will not be redistributed.

If the route map is being used for policy routing and a packet matches a statement with a deny action, the packet is not policy routed but is passed back to the normal routing process for forwarding.  ...  read more »