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Summarizing routes is a significant ability to understand to go the BSCI Test and have a single stage closer to earning your CCNP. The actual binary conversions are only A part of the test, although! You’ve got to understand how to correctly use the summary routes, Which differs from one particular protocol to the following. In the previous few CCNP / BSCI tutorials, we’ve checked out https://socialhattori.com/ using the “area assortment” and “summary-address” instructions to carry out OSPF route summarization. Now, we’ll Have a look at summarizing routes in EIGRP.
We’ll use the following 4 loopback addresses in this example:
Loopback sixteen, 16.sixteen.sixteen.16 /32
Loopback seventeen, 17.seventeen.seventeen.17 /32
Loopback 18, 18.18.eighteen.18 /32
Loopback 19. 19.19.19.19 /32
On R1, we’ll put these four addresses into EIGRP AS one hundred.
R1(config-if)#router eigrp one hundred
R1(config-router)#community sixteen.sixteen.16.16 0.0.0.0
R1(config-router)#network 17.seventeen.17.17 0.0.0.0
R1(config-router)#network eighteen.18.18.18 0.0.0.0
R1(config-router)#network 19.19.19.19 0.0.0.0
R3 can be an EIGRP neighbor of R1, and that router’s EIGRP routing table now looks like this:
R3#display ip route eigrp
17.0.0.0/32 is subnetted, one subnets
D 17.seventeen.17.seventeen [90/2297856] by way of 172.twelve.123.1, 00:00:29, Serial0
16.0.0.0/32 is subnetted, 1 subnets
D sixteen.16.16.16 [ninety/2297856] by using 172.12.123.one, 00:00:36, Serial0
19.0.0.0/32 is subnetted, 1 subnets
D 19.19.19.19 [90/2297856] by means of 172.12.123.1, 00:00:08, Serial0
18.0.0.0/32 is subnetted, one subnets
D 18.18.18.eighteen [90/2297856] by way of 172.12.123.1, 00:00:22, Serial0
To perform guide route summarization, produce out the network addresses in binary and afterwards decide the point at which the addresses not Use a little bit in popular. For these four addresses, It will probably be plenty of to jot down out the main octet in binary:
1600010000
1700010001
1800010010
1900010011
Doing work from remaining to correct, the typical bits are the initial six bits – 000100xx. In decimal, this benefit is 16. The summary mask needs to be decided at the same time, Which worth is derived from Placing a “1” from the mask for each typical bit. With the main six bits all established to at least one – 11111100 – the resulting mask is 252.0.0.0. The entire summary tackle is sixteen.0.0.0 252.0.0.0.
In EIGRP, the summary deal with is really configured on an interface, not beneath the routing process.
R1(config)#interface serial0
R1(config-if)#ip summary-tackle eigrp one hundred 16.0.0.0 252.0.0.0
02:39:fifty: %DUAL-5-NBRCHANGE: IP-EIGRP 100: Neighbor
172.twelve.123.3 (Serial0) is down: summary configured
172.twelve.123.two (Serial0) is down: summary configured
02:40:sixteen: %Twin-5-NBRCHANGE: IP-EIGRP 100: Neighbor
172.12.123.two (Serial0) is up : new adjacency
02:40:17: %Twin-five-NBRCHANGE: IP-EIGRP 100: Neighbor
172.twelve.123.three (Serial0) is up: new adjacency
There’s an immediate facet result below that the majority textbooks go away out. Your EIGRP adjacencies are going to appear down When you configure this summary, but they need to come back up immediately. The real key term There's “really should”. For those who configure EIGRP summary addresses on the generation community, you might want to try this in the course of non-peak hrs. The timestamps on the above mentioned instructions reveal the adjacencies have been down for about 27 seconds above the NBMA network. That’s about 30 minutes in finish-user time. 😉
Check out R3’s EIGRP routing desk.
D sixteen.0.0.0/six [ninety/2297856] by means of 172.12.123.one, 00:01:forty six, Serial0
The 4 summarized routes are no longer from the routing table, they usually are actually changed because of the summary route shown at the bottom in the routing table. Notice the mask is /5, which can be prefix notation for 248.0.0.0.
Knowing how and why to summarize routes is really a precious skill, whatever the protocol in use. But before you go ahead and take BSCI Test with your approach to the CCNP, ensure that you learn how to perform summarization with every one of the Main protocols!