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Draft Martini and Draft Kompella were the starting points toward standardizing the Layer2 VPN architectures using pseudowire emulation, both drafts addressed setting up pseudowire emulation over MPLS-based networks in order to offer Layer 2 VPN services, but each draft proposed a different approach. Members of the networking community divided themselves into two camps based on [...]

In this post we are going to discuss both CSC options that we have highlighted in the previous post in details. The two available options are either an ISP customer carrier, or a BGP/MPLS VPN customer carrier. We are going to conquer the control plane and data plane separately, in order to well understand the [...]

After I’ve completely illustrated the Inter-AS MPLS VPN solution with all its options, I’ve decided to cover the Carrier Supporting Carrier with all its options as well. It was described as Carriers’ Carriers in draft-ietf-2547bis section 9 and followed in the final RFC 4364, and was named Carrier Supporting Carrier by Cisco, and Carrier of [...]

While doing the final preparations for my CCIE SP track written exam, I reviewed my Inter-AS MPLS VPN posts and I found out that they needed some modifications to be more organized and comprehensive, please revisit the updated posts: Inter-AS MPLS VPN – The whole story (1) Option 1(10A): Back-to-Back VRF – Inter-AS MPLS VPN [...]

As we agreed in the last post, we are going to discuss the available tools and parameters for BGP performance tuning. In this post we are going to start discussing the different types of timers that BGP uses for its operation.

It is a very critical matter for a network architect (the same goes for a network operator but with a different prospective) to understand the inside out of tuning the routing protocols performance, in order to be able to conduct an appealing and effective low level design for small to large scale networks. We have [...]

Nonstop Forwarding is a feature of many features in the Cisco High Availability portfolio, we shall be covering most of it later. To check Cisco High Availability portfolio: http://www.cisco.com/en/US/products/ps6550/products_ios_technology_home.html Use Cisco Feature Navigator to find information about platform support and software image support: http://tools.cisco.com/ITDIT/CFN/jsp/index.jsp Cisco Nonstop Forwarding (NSF – AKA Graceful Restart) with Stateful Switchover [...]

In late 2007, Cisco introduced a new Inter-AS option; Option AB – This feature was introduced in the 12.2(33)SRC code. This feature combines the the best aspects of Option 1 (10A) and Option 2 (10B) (named type a and type b as per RFC4364 section 10 “Multi-AS Backbone”). Remember that type a (Option 1 AKA [...]

This approach is considered to be the most scalable, since when compared with Option 2(10B), the ASBRs need not learn all the VPNv4 prefixes, since now the MP-eBGP session will be established between the RRs (which already have all the VPNv4 prefixes by default) rather than the ASBRs, and the ASBRs will only be responsible [...]

With the ASBR-to-ASBR approach, the ASBRs use MP-eBGP to peer with each other to transport VPNv4 routes between the autonomous systems, and the VPN packets are transported as labeled packets between the ASBRs, unlike Option 10A. As we are going to see later in details, the main difference between both sub-options 2a and 2b and [...]