In one of the Discords that I’m in there was a user with a complex network consisting of a mix of DMVPN, BGP over MPLS VPN circuits, and SD-WAN. For some prefixes, the path via the private MPLS is preferred,
CCDE – Carrier Supporting Carrier
Introduction In the previous post I showed some of the options to interconnect two AS so that a customer can buy a VPN in two different locations from two different SPs. There is another technology called Carrier Supporting Carrier or
CCDE – Inter AS L3 VPNs
Introduction Sometimes a customer needs a L3 VPN between two locations where the same SP is not present. This can be on a national or international basis. It would be possible to buy an Internet circuit and run an overlay
CCDE – BGP Confederations
Introduction BGP Confederations are one of two tools a network designer has to work around the full mesh requirement of iBGP. BGP confederations are defined in RFC 5065 which obsoletes RFC 3065. This is how the RFC defines BGP confederations:
Busting Myths – IPv6 Link Local Next Hop into BGP
In some publications it is mentioned that a link local next-hop can’t be used when redistributing routes into BGP because routers receiving the route will not know what to do with the next-hop. That is one of the reason why
Unique RD per PE in MPLS VPN for Load Sharing and Faster Convergence
This post describes how load sharing and faster convergence in MPLS VPNs is possible by using an unique RD per VRF per PE. It assumes you are already familiar with MPLS but here is a quick recap. The Route Distinguisher
Some pointers on OSPF as PE to CE protocol
There was a discussion at the Cisco Learning Network (CLN) about OSPF as PE to CE protocol. I wanted to provide some pointers on using OSPF as PE to CE protocol. RFC 4577 describes how to use OSPF as PE
Scaling PEs in MPLS VPN – Route Target Constraint (RTC)
Introduction In any decent sized service provider or even an enterprise network running MPLS VPN, it will most likely be using Route Reflectors (RR). As described in a previous post iBGP fully meshed does not really scale. By default all
iBGP – Fully meshed vs Route Reflection
Intro This post looks at the pros and cons with BGP Route Reflection compared to running an iBGP full mesh. Full mesh Because iBGP routes are not propagated to iBGP sessions there must be a full mesh inside the BGP
BGP wedgies – Why isn’t my routing policy having effect?
Intro Brian McGahan from INE introduced me to something interesting the other day. BGP wedgie, what is that? I had never heard of it before although I’ve heard of such things occuring. A BGP wedgie is when a BGP configuration