As part of my job as a Senior Network Engineer, I develop procedures for undertakings of varying complexity. In this post I’m describing a technique that greatly simplifies any project where a routing domain is expected to churn (i.e. neighborships going up and down, routes flapping), when such event is undesirable. Motivation I developed this technique for a… Read More »
In designing a network, there is a question that is often missing an answer or at best, answered using some rule-of-thumb. How many spare units you should include in your BOM? Actually, do you need them at all? Disclaimer: I won’t be covering any of the really complex models. People who need them probably know about spare part… Read More »
For iBGP number of peers (i.e. the number of BGP routers inside an AS), the only significant limiting factor is that iBGP peers must be fully meshed (N.B.: not directly interconnected! An iBGP peering can span all the hops you can fit into the IP TTL field) – because it is the only way for iBGP to prevent… Read More »
Policy-based routing allows network administrator to stir traffic in directions different from the one chosen by destination-based routing and its routing protocols. This can be useful in several scenarios, namely in dual-homing to different ISPs, as well as other special cases. Using policy-based routing for dual-homing General notes on dual-homing The term Dual-homing in its most general meaning… Read More »
Speaking of L2 design, there are several aspects to the VLAN allocation on the switches: standard and extended VLAN ID ranges, reserved IDs, internal usage, protocol limitations and design best practices.