Friday, July 6, 2012

ccnp route eigrp 2

By default classful routing protocols like RIP, EIGRP will do auto-summary.

router eigrp 90
send hellos on any
and advertise these networks
no auto-summary

sh ip int br
router eigrp 90
network or
no auto-summary

show ip route
show ip eigrp neighbors
H == handle on which order routes are learned
SRTT == source round trip timer
RTO == retransmit timeout
Q == how many packets are in queue ..continuous static value above 0 means link problem ,,might be bandwidth issue
Seq num == version of the eigrp database running

router eigrp 90
no auto-summary

show ip eigrp neighbors
show ip route

show ip eigrp topology
lists all the routes---P ie Passive which is good

eigrp never says it has one successor and other FS
The route matching the FD is called the successor and the rest are FS routes

router eigrp 90
do show run | i ip route
ip route 255.255.0 Null0

How to set default route and advertise?
-one way is by static and type network but it advertises every n/w
-other way is ip default-network

ip default-network  ==default network should be classful
show ip route
S*====means candidate default
but you won't see gateway of last resort here

eigrp should not form a neighbor relationship with any interface which is not running eigrp.
when you configure a passive interface, it will stop sending hellos and not form any neighbor relationship with any interface
but it will still advertise the n/w

router eigrp 90
passive-interface f0/1

router eigrp 90
passive-interface default means everything will become passive==all loopback interface
now only turn on the interface which you want
no passive-interface

Summarization in eigrp
eigrp does it under interface

int s0/0
ip summary-address eigrp 90

R2# show ip route
If I get specific routes from another router then metric and AD doesn't matter.

How to perform unequal load balancing
eigrp has by default variance of 1 which means even though it can do unequal load balancing but does load balance on equal cost


var 2 ==two times bad route as current one

router eigrp 90
variance 2
do load balance across links which are twice bad

Advanced Implementation of eigrp
challenges poses by NBMA

FR is 2nd generation technology in the packet switched world
foundation ===connection through shared cloud

In ethernet we have MAC address, in FR we have DLCI ie simply no's
DLCI is locally significant

Hub and sopke design ==very inexpensive but if hub goes down everything goes down
full mesh == mpls ==everything connects everything
partial mesh==hybrid topology--as a redundancy backup will be there

How eigrp handles NBMA:
NBMA: broadcast and multicast are denied which cause a problem since eigrp use multicat
so eigrp can use "pseudo-broadcasts" or manual neighbors

int s0/0.1 multipoint
ip address
frame-realy map ip 102 broadcast
                             .3 103 broadcast
this is called a pseudo-broadcat feature.
Since this is multi-point so every interface is in same subnet.
router eigrp 25
neighbor ---- == whenever you use this command this will disable multicast. so you need to do this for all the neighbors

another issue is split-horizon

if you configure FR on a physical interface split horizon is disabled.
if you configure FR on a sub-interface split-horizon is enabled.===work more like point to point

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