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New Member

REDUCE OVERLOAD IN CORE

HI

IF I Have 5 separeted dist connected to the core.i have summarized to the core; i have this network.

10.1.0.0

10.2.0.0

10.3.0.0

10.4.0.0

10.5.0.0

the routing protocole is EIGRP.i dont need to confuse the core that it can reach the 10.0.0.0 network through 4 interfaces.how can i configure the 4 dist to do not confuse the CORE

ps have a look to this config

dist 1

int gig0/1

address subnet mask

eigrp sumaary-address 100 10.1.0.0 255.255.0.0

!

dist 2

int gig0/1

address subnet mask

eigrp sumaary-address 100 10.2.0.0 255.255.0.0

!

dist 3

int gig0/1

address subnet mask

eigrp sumaary-address 100 10.3.0.0 255.255.0.0

!

dist 4

int gig0/1

address subnet mask

eigrp sumaary-address 100 10.3.0.0 255.255.0.0

!

just i need to reduce the overload on the core. CONFIGURATION OF THESE DIST VERY MUCH APPRECATED + CHECK THE ABOUVE CONFIG ON THE DIST ;AND ADVISE ME WHERE IS MY MISTAKE

10xs

ali

12 REPLIES

Re: REDUCE OVERLOAD IN CORE

Hello Ali,

I guess you are having problems with EIGRP implementations.

Try Jeff Doyle's book TCP/IP good resource on the subject.

But, 1 question? Is auto-summary enabled on your routers?

Why are you concerned about a route to 10.0.0.0/8? just type no auto-summary under the EIGRP process and you're good to go.

Also, if you really concerned about "this overload" issue, check EIGRP STUB configurations.

But if you have many subnets for each /16 (10.1.0.0, 10.2.0.0 etc) then the best would be:

ip summary-address eigrp 100 under the correct interface.

The question is: how high is the cpu utilization on your routers?

for your other post I believe that your main concern would be the amount of traffic sent between the routers, not really a "overload" issue for the router itself, as youre using wireless links? am I right?

you could try something like:

ip bandwidth-percent eigrp 100 40

to reduce the amount of routing information sent between the routers.

Please let us know the exact reason for your concern.

HTH,

if it does, please rate this post.

Vlad

New Member

Re: REDUCE OVERLOAD IN CORE

hi vlad 10xs for ur reply

have a look to this config,where i'm mistake

dist 1

router eigrp 100

network 10.0.0.0

!

int gig0/1

address subnet mask

ip sumary-address 100 10.1.0.0 255.255.0.0

!

dist 2

int gig0/1

address subnet mask

ip sumaary-address 100 10.2.0.0 255.255.0.0

!

router eigrp 100

network 10.0.0.0

no auto-sumary

!

dist 3

int gig0/1

address subnet mask

ip sumary-address 100 10.3.0.0 255.255.0.0

!

router eigrp 100

no auto-sumary

network 10.0.0.0

dist 4

int gig0/1

address subnet mask

ip sumary sumaary-address 100 10.3.0.0 255.255.0.0

!

router eigrp 100

network 10.0.0.0

no auto-sumary

10xs

Re: REDUCE OVERLOAD IN CORE

summary address command is not correct.

you're sending the same summary through R3 and R4? is there a reason for this?

Check this link:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cg/hirp_c/ch07/erconfig.htm#wp1001069

HTH,

please rate all helpfull posts,

Vlad

New Member

Re: REDUCE OVERLOAD IN CORE

HI VLAD 10XS FOR UR REPLY!

CAN U PLZ CORRECT TO ME THIS CONFIG TO WORK FINE

10XS

New Member

Re: REDUCE OVERLOAD IN CORE

hi vlad

have a look to this attachment.

New Member

Re: REDUCE OVERLOAD IN CORE

hi vlad

check now the config.it will work correctly?

dist 1

router eigrp 100

no auto-summary

network 10.0.0.0

!

int gig0/1

address subnet mask

ip sumary-address 100 10.1.0.0 255.255.0.0

!

dist 2

int gig0/1

address subnet mask

ip sumaary-address 100 10.2.0.0 255.255.0.0

!

router eigrp 100

network 10.0.0.0

no auto-sumary

!

dist 3

int gig0/1

address subnet mask

ip sumary-address 100 10.3.0.0 255.255.0.0

!

router eigrp 100

no auto-sumary

network 10.0.0.0

dist 4

int gig0/1

address subnet mask

ip sumary sumaary-address 100 10.4.0.0 255.255.0.0

!

router eigrp 100

network 10.0.0.0

no auto-sumary

10xs

Re: REDUCE OVERLOAD IN CORE

core:

router eigrp 100

network 10.0.0.0

no auto-summary

DS1

router eigrp 100

network 10.0.0.0

passive-interface default

no passive-interface gi0/1

no auto-summary

int gi0/1

ip address

ip summary-address eigrp 100 10.3.0.0 255.255.0.0

DS2

router eigrp 100

network 10.0.0.0

passive-interface default

no passive-interface gi0/1

no auto-summary

int gi0/1

ip address

ip summary-address eigrp 100 10.2.0.0 255.255.0.0

DS3

router eigrp 100

network 10.0.0.0

passive-interface default

no passive-interface gi0/1

no auto-summary

int gi0/1

ip address

ip summary-address eigrp 100 10.4.0.0 255.255.0.0

DS4

router eigrp 100

network 10.0.0.0

passive-interface default

no passive-interface gi0/1

no auto-summary

int gi0/1

ip address

ip summary-address eigrp 100 10.5.0.0 255.255.0.0

But,

Your network seems to be very simple. Star configuration with all remote (DS routers) having the core as its way out.

I think even ODR will be enough to route between these routers.

and there's nothing less "overloading" (beside static routes) than ODR.

I wouldnt use it though, but take a look:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cg/hirp_c/ch12/odrconfg.htm#wp1000871

HTH,

Vlad

New Member

Re: REDUCE OVERLOAD IN CORE

hi vlad

10xs for ur reply

this config it will work correctly;and reduced the ovelod on the core.can u plz explain why u used the passive interface dfault;than no passive interfacegig3/1.

vlad i appreciated ur help

ali

Re: REDUCE OVERLOAD IN CORE

passive default is used when you have multiple interfaces on the same subnet covered by the command:

network under router eigrp AS.

so, you dont send EIGRP packets over links you dont have (or dont need) to.

So using no passive-interface gi0/1 will make your DS routers send eigrp packets only to the CORE nowhere else.

avoiding sending multicast packets on the LAN links.

HTH,

if it does, please rate this post.

vlad

New Member

Re: REDUCE OVERLOAD IN CORE

hi vlad 10xs for ur help!

so this configuration it will work properly depending on the diagram.can u plz explain what is the effect of these command into the core into the core:

ip summary-address eigrp 100 10.1.0.0 255.255.0.0

ip summary-address eigrp 100 10.2.0.0 255.255.0.0

ip summary-address eigrp 100 10.3.0.0 255.255.0.0

ip summary-address eigrp 100 10.4.0.0 255.255.0.0

ip summary-address eigrp 100 10.5.0.0 255.255.0.0

plz explain the effect of this command

10xs

Ali

Re: REDUCE OVERLOAD IN CORE

Effects on the Core:

it will show a route in its route table like the below for each summary

D 10.2.0.0/16 [90/2195456] via 10.1.1.2, 00:02:12, Serial0

All subnets inside those /16 will be hidden inside this aggregated route.

Also, a summary route pointing to NULL will be created on the DS routers like:

D 10.2.0.0/16 is a summary, 00:03:22, Null0

This may cause problem when you have discontiguous networks, so be carefull.

the command it self will only be used if there are components of the bigger subnet in your routing table.

Meaning, if you set ip summary-address eigrp 100 172.16.0.0 255.255.0.0, and there's no route like this (172.16.1.0/24, 172.16.5.0/24 etc) on your routing table, then this aggregated route 172.16.0.0/16 wont be advertised out.

Vlad

New Member

Re: REDUCE OVERLOAD IN CORE

hi vlad

u have mentioned before that passive default is used when we have multiple interfaces on the same subnet.can u explain more?

10xs

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