I’m finally back to labbing after almost two years off. I’d like to say I have a good excuse, but I won’t bother. What’s important is that I’ve picked it up again. So let’s jump into it. Filtering EIGRP Routes with Prefix-Lists For this bit, we’ll filter routes coming in using prefix-lists. How hard canContinue reading “1.2.f Route filtering with any routing protocol”
Tag Archives: Cisco
Bonus: SD-WAN IOS Upgrade
This will be a quick post on upgrading an ASR IOS using SD-WAN. I’m going to go from 17.3.3 to 17.3.4a. We’ll just be uploading the image directly to vManage. Add Image to Repository In vManage, go to Maintenance > Software Repository > Software Images > Add New Software. Select the first option, vManage. ClickContinue reading “Bonus: SD-WAN IOS Upgrade”
1.5.a IBGP and EBGP peer relationships
Some trivia facts: Basic eBGP configuration: R1:router bgp 1 neighbor 1.1.12.2 remote-as 2 network 1.1.12.0 mask 255.255.255.0 network 10.1.1.1 mask 255.255.255.255 R2router bgp 2 neighbor 1.1.12.1 remote-as 1 network 1.1.12.0 mask 255.255.255.0 network 10.1.1.2 mask 255.255.255.255 Basic iBGP configuration: R1:router bgp 1 neighbor 1.1.12.2 remote-as 1 network 1.1.12.0 mask 255.255.255.0 network 10.1.1.1 mask 255.255.255.255 R2:routerContinue reading “1.5.a IBGP and EBGP peer relationships”
1.4.e Optimization, convergence and scalability (OSPF)
1.4.e i Metrics I already covered OSPF metrics in the previous post, so I’ll skip it here. I may come back and move things around later to make it easier to find stuff. 1.4.e ii LSA throttling, SPF tuning, fast hello LSA Throttling (OSPFv2) https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_ospf/configuration/xe-16/iro-xe-16-book/iro-lsa-throt.html LSA throttling does two things. Firstly, it’s gets us awayContinue reading “1.4.e Optimization, convergence and scalability (OSPF)”
1.4 OSPF (v2 and v3)
1.4.a Adjacencies A quick review of everything we need to remember for adjacencies to form: Unlike EIGRP, the hello timer and dead timer in OSPF must match. Remember the dead timer is 4x the hello timer, not the typical 3x. We’ll probably be tasked with tweaking these in the lab. interface gig 0/0 ip ospfContinue reading “1.4 OSPF (v2 and v3)”
1.3.f v EIGRP stub with leak map
Stub Routers:As we learned in 1.3.c iii, routes hang out in the active state waiting for a reply to the query they sent. What if we know for sure that the route we’re trying to learn about is definitely not down that alley behind that building over there. Do we really need to send queriesContinue reading “1.3.f v EIGRP stub with leak map”
1.3.f Optimization, convergence and scalability (EIGRP)
Optimization comes down to three things: Failure detection: How fast can we figure out something’s wrong? (We should use BFD here, but let’s pretend we can’t because the task tells us not to.) Information propagation: How fast can we tell our neighbors about the failure? Fault repair: How fast can we calculate an alternate path?Continue reading “1.3.f Optimization, convergence and scalability (EIGRP)”
1.3.e EIGRP Named Mode
Updated 11/5/23 to include unicast vs multicast neighbors and the no next-hop-self command.The nice thing about Named Mode is everything is (sort of) in the same place, instead of some config being under router eigrp and some config being under individual interface configs. Is that it, it’s just more organized? There are also these advantages:Continue reading “1.3.e EIGRP Named Mode”
1.3.d EIGRP load balancing
1.3.d i Equal-cost Enabled by default, as long as the metrics match. Nothing really to do here. 1.3.d ii Unequal-cost Use the variance command. The only trick is when you multiply your best path’s metric by the configured variance, the product has to be higher than any potential path’s metrics, otherwise they still won’t beContinue reading “1.3.d EIGRP load balancing”
1.3.f iv Leak-map with summary routes (EIGRP)
A quick look at our topology: Let’s set up a summary route for the following loopbacks on R20. R20interface lo104 ip add 10.10.104.1 255.255.255.0interface lo105 ip add 10.10.105.1 255.255.255.0interface lo106 ip add 10.10.106.1 255.255.255.0interface lo107 ip add 10.10.107.1 255.255.255.0 router eigrp 10 network 10.10.104.0 0.0.0.255 network 10.10.105.0 0.0.0.255 network 10.10.106.0 0.0.0.255 network 10.10.107.0 0.0.0.255 SummarizationContinue reading “1.3.f iv Leak-map with summary routes (EIGRP)”
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