TSHOOT – Gigantic BGP review, verification commands, and troubleshooting for exam day!

This will be the BGP Topology you will very likely be working Trouble tickets from on the TSHOOT, it could be iBGP or eBGP, and there is a whole lot of BGP to know even for that! Review of BGP BGP is called a "Path Vector" Protocol that basically is the internet at Layer 3, … Continue reading TSHOOT – Gigantic BGP review, verification commands, and troubleshooting for exam day!

TSHOOT – Redistribution Part 5 – The OSPF / EIGRP / BGP / Redistribution lab!

To round off Redistribution series of posts for Dynamic Routing Redistribution, what better way to drive it home, than to Redistribute every Dynamic Routing Domain into every other one and see what we can break? There will be a LOT of output from this lab to demonstrate how to verify and configure / troubleshoot everything … Continue reading TSHOOT – Redistribution Part 5 – The OSPF / EIGRP / BGP / Redistribution lab!

TSHOOT – Redistribution Part 3 – OSPF, OSPFv3, and BGP Redistribution review and troubleshooting!

I will wrap this up with a look at OSPF and BGP Redistribution, above is a Topology I labbed during ROUTE studies of the BGP MED concept, this is to demonstrate visually the difference of iBGP vs eBGP being the AS that BGP Routers reside in. Troubleshooting Redistribution into OSPF and OSPFv3 OSPF is very … Continue reading TSHOOT – Redistribution Part 3 – OSPF, OSPFv3, and BGP Redistribution review and troubleshooting!

Prefix-Lists and BGP, fundamentals and configuration explained, important behaviors and more to know for exam day!

BGP Prefix lists are important for their high flexibility, support for incremental updates, and that writing BGP Prefix lists are much more efficient than writing ACL's that filter BGP updates as BGP tables can have much more content (thousands of entries) in them as compared to IGP's route tables. They have some similarities to ACL's … Continue reading Prefix-Lists and BGP, fundamentals and configuration explained, important behaviors and more to know for exam day!

iBGP: Full Mesh vs Non-Full Mesh, Synchronization / Transit Rule, BGP Split horizon and other important details!

Full-Mesh vs No Full-Mesh iBGP AS The only time iBGP Speakers will advertise routes is if it meets one of the following criteria: If the route was created on the local router and added via the network command If you configure static route or IGP route redistribution If the route is a directly connected route … Continue reading iBGP: Full Mesh vs Non-Full Mesh, Synchronization / Transit Rule, BGP Split horizon and other important details!

BGP Route Aggregation / Summarization explained, configured, and some important details for exam day!

I'd like to start off with a quick example of the output from when I was adjusting routers from the previous lab for this lab, by doing "no router bgp 123" on it and creating AS 15 on it, with a neigbor statement point at 172.12.15.5 and went to R5 to do the same: *Apr … Continue reading BGP Route Aggregation / Summarization explained, configured, and some important details for exam day!

Local Preference Part 2: Configuring the “Some but not all” local preference attribute, behaviors, and explanations!

Same Topology, only this time I added a second logical network between R3 and R4 by creating 2 loopback interfaces in the same subnet 210.3.3.0 /24, and removed the previous "All or none" configuration for Local Preference. So first I want to review R2 and R1 to see if their ip bgp tables look correct: … Continue reading Local Preference Part 2: Configuring the “Some but not all” local preference attribute, behaviors, and explanations!

The Local Preference attribute explained, and the ‘All or nothing’ way of configuring it and behaviors explained!

So as can be seen, once again we've ditched the NBMA as this Topology of a shared Ethernet segment will better illustrate Local Preference explanation, behaviors, etc. ***For labbing example purposes I want to point out there is another link in the above Topology, R3-R4 is connected by the Fa0/1 link on the network 172.12.34.0 … Continue reading The Local Preference attribute explained, and the ‘All or nothing’ way of configuring it and behaviors explained!

BGP – The Multi-Exit Discriminator (MED) / Metric explained, configured, and we see some old friends ACL’s and Route-Maps to help accomplish the goal!

So as can be seen we have no NBMA in this topology, only Serial Links and an Ethernet segment, which almost makes feel naked without a Frame-Switch in there somewhere. So to begin, my last post included on the tail end a "sh ip bgp" to demonstrate something with a bunch of loopbacks being advertied … Continue reading BGP – The Multi-Exit Discriminator (MED) / Metric explained, configured, and we see some old friends ACL’s and Route-Maps to help accomplish the goal!

BGP Attribute Intro – Foundational information that you MUST KNOW before getting into BGP attributes!!!

In my first post with BGP, when I said the key to success with BGP is knowing the "Attributes" of it, specifically which are well-known and which are optional. This is VERY important information to get a foundation understanding of BGP attributes. These are the 4 types of Attributes, the attributes themselves, and explanation below: … Continue reading BGP Attribute Intro – Foundational information that you MUST KNOW before getting into BGP attributes!!!

BGP Intro: Comparison to EIGRP behaviors, Cisco Best Practices, and BGP Peering explained before the labs begin!

BGP is an internet protocol that allows groups of routers (called Autonomous Systems) to share routing information, so efficient loop free paths can be established, and that sounds exactly like what EIGRP already does so what is the need for BGP? I am glad I asked: BGP is an Exterior Gateway protocol that runs between … Continue reading BGP Intro: Comparison to EIGRP behaviors, Cisco Best Practices, and BGP Peering explained before the labs begin!