Yesterday we had a customer network migration from IPsec VPN to MPLS. Customer’s headquarter network wanted to be the point of internet sharing so that all branch offices use that point for internet browsing. OSPF was chosen to be the dynamic routing protocol between CE and PE, as ASA is deaf to BGP. We configured [...]
Archive for the ‘IP Routing’ Category
1 Nov
CCIE SP – MPLS Traffic Engineering
TE was the main driver and reason for MPLS invention. To utilize bandwidth of unused links, to have flexibility in path selection just like previous WAN switching technologies. To create Virtual circuits on top of IP networks. IP Routing is performed hop by hop and you can not dictate a policy to other hops. TE [...]
15 Oct
CCIE SP – MPLS VPN Carrier Supporting Carrier
The carrier supporting carrier feature enables one MPLS VPN-based service provider to allow other service providers (Tier2) to use its backbone network for connectivity of their POPs. It is also called a carrier-of-carriers VPN. It is a two-tiered relationship between a provider carrier and a customer carrier. In a carrier-of-carriers VPN, the provider carrier provides [...]
14 Oct
CCIE SP – Inter-AS MP-BGP with RR
In MP-BGP, VPN label assignment is always performed by BGP next hop. In the following picture, if we create eBGP relationship beween R3 and R1 (instead of R2), VPN label from CE (R5) to other CE (R4) will point to R1 as R1 is the next hop for R3. The reason behind this is simple, [...]
13 Oct
CCIE SP – Multihop MP-BGP for Inter-AS MPLS VPN
The third option for Inter-AS MPLS VPN is using multihop feature of eBGP between VPNv4 PE routers directly from one SP to another one. In the previous posts, we reviewed two other options: Back to back VRF Inter-AS MPLS VPN External MP-BGP for VPNv4 In the multihop MP-eBGP, LSP is built end-to-end by PE routers [...]
12 Oct
CCIE SP – External MP-BGP for VPNv4
In the previous post, we reviewed VRF-to-VRF Inter-AS MPLS VPNs, now we want to go over the other option, which is the use of MP-eBGP at ASBRs for prefix exchange. This method is more scalable and felixable than back-to-back VRFs and only one interface is required between providers routers. No VRF is required. Automatic Route [...]
12 Oct
CCIE SP – Back to Back VRF Inter-AS MPLS VPN
When customer’s sites are connected to different MPLS providers, there are several options available for providers to connect customer sites just like regular MLPS VPNs transparent to customers. In our example below, the Customer1 has two sites, each connected to an individual service provider. Service providers have several options to achieve this goal, the simplest [...]
11 Oct
CCIE SP – BGP as PE-CE
Usually service providers assign a unique AS number to each customer’s site for MPLS BGP routing (between PE and CE)… In our example, the Customer1, our favorite customer has four sites using R4, R5, R6 and R7 from AS64 to 67 to use MPLS backbone as transit network to deliver their applications. Customer1 is peering [...]
11 Oct
CCIE SP – OSPF Super-Backbone
Once upon a time there was RIP and not so many problems with its simplicity! Nowadays networks are larger in scale and more complex in action, convergence time and redundancy are more important than ever. It’s not too bad, lots of fun for us… Once the customers want to use OSPF on C Routers, we [...]
10 Oct
SOO for EIGRP – Site-of-Origin
To speed up the reconvergence of EIGRP in MPLS networks -when there’s a backdoor link between sites (outside of MPLS boundary) EIGRP uses SOO extended community attribute to tag the site of origin of particular routes for each site. This method reduces the time of convergence as it eliminates count to infinity of EIGRP which [...]
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