Cisco CCNP Certification / BSCI Exam Tutorial: Floating Static Routes
Passing the BSCI examination and earning your CCNP certification demands that you add tremendously to the networking skills foundation you created whenever you studied in your CCNA certification. You learned quite a bit about static routing and default static routing while you handed the CCNA test, and it does look like that needs to be all you have to learn about static routing, right?
One factor you may study as you continue to earn Cisco certifications is that there’s always something else to learn! You’ll have heard the term “floating static route”, which does recommend some attention-grabbing psychological pictures. “Floating”? Floating on what?
In a manner, a floating static route is “floating” in your routing table. A floating static route is a route that will likely be used only if routes for a similar vacation spot however with a lower administrative distance are faraway from the table. For instance, you possibly can be using an OSPF-found route as your major path to a given vacation spot, and the floating static route would serve as a backup route that might be used only if the OSPF route leaves the routing table.
Now, how can that happen? In any case, OSPF has an administrative distance of 110 and static routes have ADs of one or zero, depending on whether or not it’s configured with a next-hop IP tackle or an area exit interface. Come what may, 1 and 0 are nonetheless less than a hundred and ten!
Once you want to configure a floating static route, you should assign the route an AD larger than that of the primary route. In this case, we have got to create a static route with an AD increased than 110. We do this through the use of the “distance” option on the finish of the “ip route” command.
R1(config)ip route 110.1.1.zero 255.255.255.zero 172.12.123.1 ?
Distance metric for this route
identify Specify name of the subsequent hop
permanent permanent route
tag Set tag for this route
R1(config)ip route 110.1.1.zero 255.255.255.0 172.12.123.1 111
The number entered at the very finish of the “ip route” command is the AD of that route. If there’s an OSPF route for 110.1.1.0 /24, that would be the major route, and the floating static route is not going to be used except the OSPF route is taken out of the routing table.
Floating static routes aren’t only a good thing to know for the BSCI examination and your CCNP certification pursuit – they’re very sensible in the true world as well.
In my final ISIS tutorial, I mentioned that while ISIS and OSPF are each hyperlink state protocols, their precise operation differs greatly. To go the BSCI exam and earn your CCNP, you’ll must know these variations! In the present day, we’ll check out ISIS Good day sorts and the adjacency types that type by way of the use of these Hellos.
Hiya packets have been mentioned a number of instances with ISIS, and with good reason. Good day packets are the heartbeat of OSPF and ISIS when heartbeats are not heard from a neighbor, that adjacency will be dropped. A serious difference between OSPF and ISIS is that OSPF has one kind of Whats up packet, the place ISIS actually has three!
An ES Whats up (ESH) is ship by all Finish Programs, and all IS units hear for this Hello. This is how a router (IS) discovers a host (ES).
An IS Good day (ISH) publicizes the presence of an IS. An IS Howdy is distributed by all IS devices, and Finish Systems pay attention for these hellos.
An IS-to-IS Hello (IIH) is utilized by an IS to find different ISes and to form adjacencies with them.
An attention-grabbing side be aware: A router will send an IIH to another router on the link to form or keep an adjacency, however it will still send an ISH as nicely in case there are finish systems located on that segment.
ISIS and OSPF each create and preserve adjacencies with the Hiya packet. Let’s take a look at the rules concerning ISIS adjacencies in addition to the adjacency types.
L1 and L2 Hellos are completely different messages, so an L1 router should alternate Hellos with one other L1 router to kind an adjacency, simply as L2 routers form adjacencies with L2 routers. L1 routers can solely kind an adjacency with an L2 router if one of many two routers concerned is definitely an L1/L2 router.
L1 routers must be in the identical area to be able to kind an adjacency. The Whats up timers, as well as the MTU, should match between the interfaces used to kind the adjacency.
That’s lots of L1, L2, and L1/L2, is not it? Let’s overview the adjacencies every router sort can form:
L1: Can form adjacency with any L1 in the identical area and any L1/L2 in the same area.
L2: Can form adjacency with any L2 in any space, and with an L1/L2 in any area.
L1/L2: Can kind adjacency with any L1 in the same space, L1/L2 in any space, and L2 in any area.
Figuring out the similarities and differences regarding ISIS and OSPF is significant for CCNP exam success. Take your time, master the fundamentals, and before lengthy the magic letters “CCNP” are behind your title and in your resume!
You’ll be able to read extra in my site , i’m joyful that you simply read my article, thnak you , you’ll be able to go to right here
best dvd player computer
Processing your request, Please wait....
