05-07-2007 01:21 AM - edited 03-05-2019 03:54 PM
Hello Experts!
i Have 1 CORE 6507 SUP-720 and other 3 Sites in every site we have 6509-sup2.EIGRP Is a the Routing Protocole.i Need to perform summarization;this summarization should be done toward the core or from the core toward DSs
10xs
05-07-2007 01:33 AM
Hi,
To configure a summary aggregate address , use the "ip summary-address eigrp as-number network-address subnet-mask" command in interface configuration mode
interface ethernet 0
ip summary-address eigrp 109 192.168.0.0 255.255.0.0 --> Note that the subnet mask here is not written as wildcard
The router will advertise the summarized route only to its neighbor through this interface, while adding the summarized route to its null interface in its routing table and keeping the more specific route to be used when the neighbor routed packets arrived in order to be used.
NOTE: EIGRP summary routes are given an administrative distance value of 5 by default, can be changed in the summary command.
NOTE: The more specific route needs to be in the routing table for the summary route to be originated.
HTH, please rate all helpful posts,
Mohammed Mahmoud.
05-07-2007 01:54 AM
Hi mohammedmahmoud!
10xs for ur reply;the summarization FROM THE CORE TOWARD THE DSs Or From the DSs toward the Core
05-07-2007 01:56 AM
hi,
You should do the summarization from the DS towards the Core.
HTH, please do rate all helpful replies,
Mohammed Mahmoud.
05-07-2007 02:12 AM
HI mohammedmahmoud!
Kindly check attached file;so what this config does;sumarization from the CORE Toward the DSs
CORE!
Interface Portchannel200
descr connection to DS1
ip address 192.168.200.1 255.255.255.252
ip summary-address eigrp 1 10.250.0.0
!
Interface Portchannel100
descr connection to DS2
ip address 192.168.200.37 255.255.255.252
ip summary-address eigrp 1 10.250.0.0
!
Interface Portchannel1
descr connection to DS3
ip address 192.168.200.29 255.255.255.252
ip summary-address eigrp 1 10.200.0.0
!
***************************
CORE:Network:10.100.0.0 *
DS1: Network:10.200.0.0 *
DS2: Network:10.200.0.0 *
DS3: Network:10.250.0.0 *
***************************
this config work perfect but i didn't undesstand why the Summary from the CORE Towards the DSs.plz explain
05-07-2007 05:34 AM
Hi,
For the best practice you should do the summarization from the DS towards the Core, may be in your case there was a special issue to be considered, may be due to the direct link between DS1 and DS2.
HTH,
Mohammed Mahmoud.
05-07-2007 09:12 AM
Hi!
can u expain in wich cases we will sumarize from the CORE To the DSs
05-07-2007 08:05 AM
HI Ali
the config is missing subnet mask in the
ip summary-address eigrp 1 10.200.0.0 (subnet mask)
Thanks
Mahmood
05-07-2007 09:24 AM
also at the routing table i have seen a default route(s*) to to a null interface;from where came to the routing table/what its role does
10xs
05-07-2007 10:16 AM
Hi Ali,
When doing EIGRP summarization using this command, the router adds a summary route to null in its routing table automatically and advertise this route, but when the packet to be routed arrives at the router it is routed via the more specific route rather than this null route. (note that the route won't be summarized in the first place unless the more specific route was there).
HTH, please do rate helpful replies,
Mohammed Mahmoud.
05-07-2007 10:27 AM
Hi Mahmoud !
just 1 thing:can u expain in wich cases we will sumarize from the CORE To the DSs
10xs
05-07-2007 10:41 AM
Well if you can look at in a logical way. Your core router would have more routes, routes from external routers, you probably could have a ton of information there, but you would for your distribution switches which may have lesser processing power to have lesser overheads when trying to reach external routes. For reaching any of your external routes or destination a simple default route (summarizes everything) would be just enough on your distribution. Your core could do more specific routing once the packet is recieved there.
-Hoogen
Do rate if this helps :)
05-07-2007 11:48 AM
Hi,
As a best practice we do summarize from the distribution layer into the core via summary-address, summarization within the core is unnecessary. Because each distribution layer router is sending only summary information to the core, it is probably unnecessary to further summarize between core routers. However sometimes it is useful to summarize between core routers, or between the core and the distribution to minimize routing tables more, especially when the distribution routers are not that powerful.
HTH,
Mohammed Mahmoud.
05-08-2007 09:37 AM
Hi !
so i want to add another DS(DS4)the Network WOULD BE 10.150.0.0.noW from the Core Side wich summary should i send to the DS4 via the New L3 port-channel connected to the DS4 Based on my Attached DIAGRAMs
10XS
05-08-2007 09:42 AM
Ali,
Attachment is missing.
-amit singh
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