[python]Automating OSPF configuration of two routers

Network diagram There are two vIOS which are R1 and R2, they have their gi0/2 and gi0/3 connected to the R5 switch, the configuration is pushed from the cloud through their gi0/2 and gi0/3 to configure their gi0/0 to become OSPF neighbours. Objective To configure the two routers to become ospf neighbors, the OSPF configuration … Continue reading [python]Automating OSPF configuration of two routers →

Extending the python script to configure OSPF with ncclient

Previously I have successfully download the configuration from the netconf enabled router, now i have extended support to configure ospf. This is a simple lab to further extend and get myself familiarize and comfortable with netconf. During the lab I was careless, I inadvertently left a space on my netconf snippet that breaks my script … Continue reading Extending the python script to configure OSPF with ncclient →

OSPF virtual link with message digest authentication

Dis-contiguous area Non-backbone area has to be converged with backbone area (area 0) in order for OSPF to learn the routes. The following example has area 100 discontiguous with backbone area, the solution is either to use GRE tunnel or virtual link. Virtual link 1. Router-id is used for virtual-link neighbor not the IP address … Continue reading OSPF virtual link with message digest authentication →

Palo Alto Networks: OSPF and L3 Link aggregation

The previous post about Cisco VSS is to integrate with Palo Alto Firewalls. Layer 3 link aggregation on PA firewall Click on Network tab and select Interfaces from the menu on the left. There is an "Add Aggregate Group" at the bottom of the page, it may seem quite unnoticeable. After the link aggregation link … Continue reading Palo Alto Networks: OSPF and L3 Link aggregation →

MPLS: OSPF sham-links

Introduction The provider's MPLS cloud has three routers namely - R1 (P-router), R2 (PE-R2) and R3 (PE-R3). These routers formed OSPF adjacency with one another. R2 and R3 are iBGP neighbors peering with each other's loopback address. The TTL propagation within the MPLS cloud was suppressed with no mpls ip propagate-ttl command. This is to … Continue reading MPLS: OSPF sham-links →

MPLS Layer 3 VPN

Acknowledgement Without MR.Keith Barker's 21 minutes video instruction, constructing MPLS VPN lab will take a longer time. His 21 minutes video instruction summarizes all. MR. Keith Barker has amazing skills to translate complicated concepts into simpler and easier to understand concepts. Now it is clearer to me and I believe it will be easier on … Continue reading MPLS Layer 3 VPN →

BGP: Injecting IGP route into BGP without redistribution

The diagram is complicated with an additional link, and instead of full BGP route in AS65000, the BGP route is propagated with the help of OSPF. In previous lab, the BGP full mesh was established by peering both subnets of a BGP router. However this step can be simplified by peering the BGP speaker's loopback … Continue reading BGP: Injecting IGP route into BGP without redistribution →

Multi Protocol Label Switching basics

MPLS label 1. 32-bit long. 2. First 20 bits for label, second 3 bits for EXP which is used for quality of service, third 1 bit for bottom of the stack, last 8 bits for time to live. 3. Here is the break down: a. bit 0 to bit 19: Label. b. bit 20 to … Continue reading Multi Protocol Label Switching basics →

Type 10 LSA – Opaque LSA

This LSA is an extension of OSPF. The extension is for doing OSPF traffic engineering. MAX-LSA - Protects against adjacent router's excessive LSA in the OSPF domain. Excessive LSA will cost router's high cpu resources. This is to limit the LSA that is not generated by the router itself. CAUTION: Router adjacency will be affected … Continue reading Type 10 LSA – Opaque LSA →

LSA types

1. Router LSA - This LSA is produced by every router. The LSA contains information of the router's connected interfaces, states, neighbour router type, any known ospf routers connected to the router's link and outgoing cost of each link. This LSA floods within its own area (intra-area flooding), hence this LSA describes intra-area route. 2. … Continue reading LSA types →