10
votes
Accepted
Why does EIGRP aim to be loop free?
All routing protocols try to avoid a loop topology. If there is a routing loop, data is not getting to the destination.
If the path from source to destination is A -> B -> C -> D, but there is a ...
- 67.1k
9
votes
Accepted
Why do summary routes get a low Administrative Distance?
Since the summarized route means that a router advertising it has knowledge of the individual routes within the summarized prefix, it is more trustworthy than the same (summarized) prefix being ...
- 98.7k
9
votes
Accepted
When would we want to do traffic steering?
One example would be when the 'best path' is not actually desirable for the traffic in question. The selected path might be the most efficient (shortest in terms of routed hops etc.) but might ...
- 2,050
6
votes
Why do summary routes get a low Administrative Distance?
The AD of the EIGRP summary route is 5 only on the router that has the summary route configured. When the summary is advertised to other routers it has an AD of 90.
The reason for the low AD is to ...
- 67.1k
6
votes
Accepted
Why can't I ping in this situation?
You have the 10.0.0.0/8 and 172.16.0.0/16 networks defined on both the middle and right routers. Using auto-summary on both makes each think they own those whole summarized networks, so they will not ...
- 98.7k
6
votes
Accepted
What Is The Difference Between Using Wildcard Mask In EIGRP And In OSPF?
I'll assume you are referring to the wildcard mask being used with the network ... statements in EIGRP and OSPF configurations.
As in (pseudo config code)
router ospf 100
router-id <...
- 8,826
5
votes
Accepted
EIGRP metric explanation
EIGRP Metric Formula
The EIGRP Metric is a combination of a measure of the entire path's cumulative delay, and the minimum bandwidth across the entire path. The delay value is value assigned to each '...
- 14.9k
5
votes
Accepted
How do OSPF and EIGRP deal with 2 exactly same routes?
Will ospf and eigrp share the 10 network on the right to their
neighbors?
As per my understanding link state protocols like ospf do so while
eigrp being a distance vector protocol will share ...
- 1,241
5
votes
Accepted
EIGRP failover - how do i verify it happened?
There is a command made for such checking. Use:
show ip eigrp events
- 651
5
votes
Accepted
No passive-interface error
You have to put your interfaces into vrf 4.
interface fa 2/0
ip vrf forwarding 4
An interface can only be in one vrf. Otherwise, how would the router know which interface to use?
If you don't ...
- 67.1k
5
votes
Accepted
Why does EIGRP have lower Administrative distance than OSPF?
That is because Cisco determines the AD used by its devices, and EIGRP is a Cisco protocol, so Cisco decided to make EIGRP have a lower AD than other protocols.
Each vendor determines the relative ...
- 98.7k
5
votes
Ramifications of turning off Spanning Tree for EIGRP network?
Spanning-tree is a loop detection / prevention mechanism. As such, it has nothing to do with EIGRP. Unless you have loops, or parallel layer-2 links in the network, STP isn't doing anything for you. ...
- 31.7k
4
votes
Accepted
Choosing a routing protocol
To choose a routing protocol you should consider these topics:
Configuration: How easy is to configure and troubleshoot the protocol.
Efficiency: How fast it converges? How much bandwith it uses?
...
- 4,487
4
votes
Why I cant Ping An Address across my a routed link
If you are talking about L3 interfaces and EIGRP, we must assume this:
Network1: Switch1 - Firewall
Network2: Switch2 - Switch1
First. You need to set-up on your firewall EIGRP(on the way to LEARN ...
- 2,105
4
votes
Accepted
How does EIGRP determine the path to far away destinations?
There seems to be a confusion here : in a distance-vector routing protocol, the routers don't just get routes to their neighbors (which would be trivial in most cases) they get their neighbor's full ...
- 2,449
4
votes
EIGRP failover - how do i verify it happened?
Yes, you can confirm that. Once hold-time expires, the former
feasible successor route immediately becomes the successor route and
is installed in routing table.
I do not think we have a log message ...
- 3,754
4
votes
No passive-interface error
From your configs, interface FastEthernet2/0 is not part of vrf 4 that your EIGRP is configured for oneither of your routers. Try adding your interface to the vrf with the following.
interface ...
- 536
4
votes
Accepted
Filter routes based on interface
You can specify what routes exactly you want to receive from neighbor on specific interface by using distribute-list option:
(conf)# router eigrp 10
(config-router)# distribute-list 50 in Tunnel 3
...
- 2,774
4
votes
Accepted
EIGRP authentication on GRE tunnel interface?
Yes, you can do that. Below is an example:
Router-A#
!
key chain Netlab
key 13
key-string Netlabbuilder
!
interface Tunnel1
description Site-B
ip address 10.99.99.1 255.255.255.252
ip mtu 1400
...
- 3,754
4
votes
Accepted
EIGRP Auto-summary
Auto-summary summarizes network advertisements based on classful boundaries. Since classful addressing has been obsolete since before you were born, it's good practice to disable it.
- 67.1k
4
votes
Accepted
Ramifications of turning off Spanning Tree for EIGRP network?
switch that has elected itself
You should never leave the root bridge to chance. If the current root switch goes offline or is rebooted your spanning tree needs to reconverge, causing temporary ...
- 82.6k
4
votes
In router's config, why do I need to advertise the directly connected network?
I think you misunderstand the OSPF and EIGRP network statement. The network statement does not advertise a network, it tells the routing protocol which interface(s) to include in the routing protocol ...
- 98.7k
4
votes
Accepted
Running multiple EIGRP processes on a router
Running multiple processes is not very common and there are not a lot of examples.
One possible reason for running multiple processes is when there are two separate routing domains (e.g. when merging ...
- 67.1k
4
votes
Accepted
Doesn't OSPF Have Auto Summarization?
I'm not going to get into the specifics of the various protocols other than OSPF because it is a good example to start with and it gets confusing if you pull in completely different things. Details ...
- 2,050
4
votes
Accepted
Interior vs Exterior Gateway Protocols
In practice, there is only one EGP in use today, and that is BGPv4. OSPF and EIGRP are the most common IGPs. RIP is essentially obsolete.
Can a company private network be considered as an ...
- 67.1k
3
votes
Keep EIGRP up even through an interface flaps
Have you considered setting the link debounce timer to a higher value than its default (which I think is 100ms)? This basically delays the notification that the link has flapped, and can affect ...
- 585
3
votes
Accepted
This is an EIGRP Topology with frame relay. I'm not able to figure out why R1's topology table doesn't a show feasible successor for 192.168.2.0/24
I'm not able to figure out why R1's topology table doesn't show
feasible successor for 192.168.2.0/24?
Remember the feasible successor rule: A feasible successor is a path whose reported distance ...
- 98.7k
3
votes
BGP problems, cannot ping
You have not set the clock rate on the DCE side of the connection. The command is clock rate <rate>. See Cisco IOS Interface and Hardware Component Command Reference.
Another problem is that ...
- 98.7k
3
votes
Accepted
Preventing Load balancing in EIGRP
If you simply want to prevent load balancing, then you can use the maximum-paths command in EIGRP to do that. Just set it to 1:
router eigrp 1
maximim-paths 1
EIGRP Commands:
maximum-paths (...
- 98.7k
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