Routing – Page 2 – routingloop.net

AS Boundary Links in IGP?

14DecemberStevenENSLD, Home Lab, Routing

Lately I’ve been focusing on honing my BGP skills to prepare for the ENSLD exam. While this isn’t a configuration focused exam, I’ve been spending some lab time on it to reinforce design concepts. I built out a 29-node lab in Cisco modeling labs featuring eBGP, iBGP, route reflectors, BGP confederations, and eBGP third party

Information Hiding in Routing Systems

19NovemberStevenHome Lab, Routing

One of the most effective methods to build stable and scalable routing designs is to summarize topology and reachability information in routing protocols. Summarization can help networks converge faster and limit the number of routers that need to perform route calculations when an event such as a link flap occurs. However, there are tradeoffs to

Static Routes, Exit Interfaces, Ethernets

9SeptemberStevenHome Lab, Routing

Ethernet Ethernet allows multiple hosts to share the same network segment. There are only 3 ways to deliver a frame to another computer over ethernet. You can send a broadcast and interrupt every host on the segment, send a multicast and hope that the intended receiver is listening, or send a unicast by placing the

Faster EIGRP Feasible Successor Failover

10AugustStevenHome Lab, Routing

The feasible successor is EIGRP predetermining an alternate next hop to reach a destination for fast failover. The feasible successor route is stored in the EIGRP topology table but is not installed in the RIB/FIB by default. The variance command can be used to promote the feasible successor to the routing table and traffic will

OSPF in Phase 1 DMVPN Networks

21JuneStevenENSLD, Home Lab, Routing

When designing hub and spoke networks, most architects will opt for distance or path vector routing protocols when given the choice. I don’t blame them, distance/path vector provides several benefits that work well in hub and spoke topologies. EIGRP based hub and spoke networks can scale to thousands of spokes without much work. Route summarization

OSPFv2 Link State Advertisements

14MayStevenHome Lab, Routing

Link State Advertisements (LSAs) are one of hardest things to understand while learning OSPF. I believe that having a basic understanding of the LSA types and being able to interpret them is crucial to understanding OSPF operation. LSAs are flooded to populate the Link State Database (LSDB) on routers participating in OSPF. The content of

It works! (kinda)

25MarchStevenHome Lab, Routing

We finally have spoke to spoke traffic working in our phase 1 DMVPN! After fixing the BGP third party next hop issue described in the last post we still had reachability issues between spokes. The spokes could reach the hub and the hub could reach the spokes just fine. Traffic transiting the hub to route

Home Lab DMVPN Lessons Learned

19MarchStevenHome Lab, Routing

My last post was about the home-to-home DMVPN we’ve been working on. The design intent was to build a phase 1 DMVPN so spoke to spoke traffic should use the hub as a transit node. It wasn’t until we tried to forward traffic from spoke to spoke that we realized we have issues. Spoke to

Home to Home DMVPN and Raspberry Pi Wireless Links

17MarchStevenHome Lab, Routing

Some months ago, I got in contact with one of my old colleagues and friend. Our discussion led to trying to decide what to do next with our home labs. He mentioned that he has a small block of provider assigned public IPv4 addresses. We got what seemed like a crazy idea – “Let’s do

eBGP, TTL and Connected-Check

4MarchStevenHome Lab, Routing

It is well known that eBGP packets default to having a Time to Live (TTL) value of 1. This has caused confusion for many network practitioners who wish to run eBGP between loopback addresses of directly connected routers. This misunderstanding sometimes leads to ebgp-multihop being configured when it is not necessary. This also gave me

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Category Archives: Routing