Categories R&S

OSPF – Optimize convergence and scalability – LSA and SPF throttling and pacing

Those timers control how often happens SPF calculation and LSA sending.   Theory: OSPF throttle timers control the interval for SPF calculation. OSPF pacing timers control the rate at which OSPF LSA flood pacing, retransmission pacing, and group pacing updates occur.   Please check the following post from INE, as this is the best explanation […]

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Categories R&S

OSPF – Implement and troubleshoot filtering – Database filtering

That’s the last part of the implement and troubleshoot filtering series.     Theory: Database filtering can be used to filter outgoing LSA on an OSPF interface. Hello packets are still exchange, so neighbor relationship is maintain but LSA advertisement are stops.   Requirements: Make sure that R4 doesn’t receive any advertisement from R1.   […]

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Categories R&S

OSPF – Implement and troubleshoot filtering – Forwarding address suppression

Let’s now have a look at this other feature.   Theory: Forwarding address suppression causes routers that are configured not to advertise forwarding addresses into the backbone to direct forwarded traffic to the translating NSSA ASBRs.   Requirements: – Configure area 2 as NSSA. – Filter R5 loopback (5.5.5.5) from being advertise into area 0 […]

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Categories R&S

OSPF – Implement and troubleshoot filtering – Route-map

Let’s move one to another way of filtering traffic in OSPF.   Theory: Route-maps can be used in conjunction with distribute-list to filter traffic. Only inbound filtering is supported and this is local to the router routing table.   OSPF database advertisement are not affected when using route-map filtering.     Requirements: Make sure traffic […]

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Categories R&S

OSPF – Implement and troubleshoot filtering – Administrative distance

Let’s now have a look at using administrative distance to filter routes.   Theory: With OPSF, administrative distance can be changed per-prefix or per-neighbor. When setting an administrative distance of 255, the route cannot be installed in the routing table. The IP address use with the distance command refer to the originator of the prefix […]

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