CCNP BSCI Notes – Scalable EIGRP

Ensurepass

Configuring

Enabling EIGRP:

       clip_image002

Adding a network to EIGRP:

      clip_image004

All interfaces belonging to the specified network will become EIGRP capable and advertised via EIGRP.

EIGRP will summarize to classful boundaries by default.

An interface can be set to ”passive” to prevent advertisement:

       clip_image006

If an interface is included in the network configuration but set to passive, it will still be included in EIGRP advertisements. If an interface is not included in an EIGRP network, it will not be advertised in EIGRP.

Summarization

Summarization is key to preventing looping route queries (which leads to SIA condition).

Disable automatic summarization to classful addresses:

       clip_image008

Configure manual summarization on an interface:

       clip_image010

Stub Routers

Stub routers participate minimally in EIGRP, which reduces utilization of memory and CPU on the router.

Often used in lieu of static routes in a hub-spoke topology to provide a standard configuration for all spoke routers.

       clip_image012

         receive-only – Prevents the router from advertising any routes

         connected – Permits advertisement of connected networks (default)

         static – Permits redistribution of static routes

         summary – Advertises summary routes (default)

Load Balancing

EIGRP automatically load balances across equal-cost links.

Unequal-cost load balancing is enabled by specifying a variance. Feasible successors with a feasible distance less than (best path FD * variance) will be proportionally utilized.

       clip_image014

Variance can be between 1 and 128; default is 1 (equal-cost only).

EIGRP Tuning

EIGRP timers do not have to match for two routers to form an adjacency.

Default hello timer:

         High-bandwidth links (>= T1): 5 seconds

         Low-bandwidth links (< T1): 60 seconds

Hello timers are modified per interface:

       clip_image016

Default hold timer = 3 *

Reconfiguring the hold timer is done in seconds, not as a multiplier:

      clip_image018  

Authentication

Authentication types:

         Plain-text password (insecure)

         MD5 hash

Configuring MD5 authentication on an interface:

        clip_image020

Bandwidth Manipulation

Bandwidth of an interface can be administratively configured:

        clip_image022

The bandwidth setting will not affect the actual interface speed, only the value used in metric calculation.

This is useful for serial interfaces which connect to a DSU operating at a slower speed.

EIGRP assumes all virtual circuits on an interface receive an equal share of the total bandwidth.

By default, EIGRP will use no more than 50% of an interface’s bandwidth. This can be adjusted as such:

         clip_image024

Verifying EIGRP Operation

Monitoring

        show ip eigrp neighbors

        show ip eigrp topology

        show ip eigrp traffic

        show ip eigrp interfaces

        show ip route eigrp

Debugging

        debug eigrp packet

        debug ip eigrp neighbors

        debug ip eigrp

        debug ip eigrp summary





[Report Dead Link] Please leave a comment or send email to report dead links, so that we will update new links within 24 hours.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.