Tag Archives: ospf

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 … Continue reading

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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 … Continue reading

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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 … Continue reading

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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 … Continue reading

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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 … Continue reading

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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 … Continue reading

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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 … Continue reading

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