What is GRE Tunnel ?

CCNA, CCNP Route
Getting Started with GRE Tunnel GRE Tunnel knows as Generic Routing Encapsulation is a tunnelling protocol developed by Cisco that provides the encapsulation of an extensive number of network layer protocols inside point-to-point links. GRE encapsulates packets into IP packets and redirects them to an intermediate host, where they are de-encapsulated and routed to their final destination. As a result of the path to the intermediate host appear to the internal datagrams as one hop, Ethernet Switches can function as if they've a digital point-to-point reference to one another. A GRE tunnel is utilised when packets must be despatched from one community to a different over the Web or an unsafe community. With GRE, a digital tunnel established between the 2 endpoints (Cisco routers), and packets forwarded by way of the…
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Difference between EIGRP and OSPF.

CCIE, CCNA, CCNA hindi, CCNP Route, networks
Hi Friends, Today I am going to write about Difference between EIGRP and OSPF, One of the questions which I have seen which asked in CCNA, CCNP interview. What is the Difference between EIGRP and OSPF? So first you should know the basics after that the main answer will come.   EIGRP Eigrp stands for Enhanced interior gateway routing protocol It uses dual ( diffuse update algorithm ) for reliability and choosing backup paths It is a Hybrid Protocol which is also known as  Advance distance vector protocol ( Combination of Distance Vector & Link state protocols ) Administrative distance = internal (90) external (170) ( External Routes when the routes Redistributed in EIGRP it shows ad value 170 in Routing table ) Eigrp is now an open standard, Cisco…
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Route Summarization

CCNA, CCNP Route
[caption id="attachment_2438" align="alignleft" width="671"] Route Summarization[/caption] Convert to Binary  First, we convert all of the 172.16.0.0 addresses above to their Binary form. 10101100.00010000 The Binary translation of these networks are: 172.16.1.0 – 10101100.00010000.00000001.00000000 172.16.2.0 – 10101100.00010000.00000010.00000000 172.16.3.0 – 10101100.00010000.00000011.00000000 Lets Summarize but  we need to locate the “Summary Border.”  To summarize these network addresses, the Summary Border needs to be located. This will be the dividing line between the “same bits ” and “different ” bits in the address.  The "same" bits are shown in Orange color  below: 172.16.1.0 – 10101100.00010000.00000001.00000000 172.16.2.0 – 10101100.00010000.00000010.00000000 172.16.3.0 – 10101100.00010000.00000011.00000000 To summarize these addresses we count the number of the “same” bits to the left of the Summary Border.  In this case, from the farthest left bit to the summary border there are 22 bits. …
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Cisco Pipe Commands

CCIE, CCIE RS, CCNA, CCNA hindi, ccna security, CCNP Route, CCNP Switching, networks
Cisco Pipe Commands This commands work on Cisco routers as well on other vendors too, Tellabs Core Routers Also Support. These commands wont work on old Ios, Try your luck friends. The following command will display the contents of the running-config, beginning with the first line containing the text ethernet: Router# show running | begin ethernet The following command will exclude all lines containing the text ethernet: Router# show running | exclude ethernet The following command will include all lines containing the text ethernet: Router# show running | include ethernet You can also use a second pipe as a OR in your expression. [su_box title="Output"] 1841#show cdp neighbors detail | inc Dev|ress: Device ID: R1605 IP address: 1.1.1.2 Device ID: R1602 IP address: 2.2.2.2 [/su_box]    
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Why we use BGP

CCIE, CCIE RS, CCNP Route, Jobs
BGP is an inter-provider protocol Or  At least that's how things started out! In a pure IPv4 world, that was the idea.   if you had PI (Provider Independent) addresses that you owned, you ran BGP to advertise them.  If you had multiple providers and were advertising the same address space multiple directions, you ran BGP to do so. Today, however, things are a little different...  In MPLS VPN environments, very often the ISP will require companies to run BGP because it makes THEIR life easier in configuration. There are memory and processing difficulties on many routers about how many different routing protocols/instances you can run.  BGP is a bit more optimized for that, so it's not that they can't run other protocols, but they simply don't. So in MPLS VPNs,…
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Eigrp Metric Calculation

CCNA, CCNP Route
Metric = (107 / minimum bandwidth) + (sum of delays) * 256 Metric = bandwidth (slowest link) + delay (sum of delays) Bandwidth: [107 / minimum bandwidth in the path] Delay: sums of delays (in tens of microseconds). 1. Bandwidth [107 / minimum bandwidth in the path]     10000000/1544 == 6476   2.  Delay: sums of delays  (in tens of microseconds).      20000 + 20000 = 40000      40000 / 10 = 4000   ( Divide by 10 because delay in  usec )   3. Metric = (107 / minimum bandwidth) + (sum of delays) * 256     4000 + 6476 * 256 =2681856 [hr] [dropcap]Router# Show ip Route Output Gateway of last resort is not set C 1.0.0.0/8 is directly connected, Serial0/0/0 D 2.0.0.0/8 [90/2681856] via…
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IBGP without IGP

CCIE RS, CCNP Route
Why bgp is in active state ? Everyone this is IBGP configuration, Dont say ebgp multihop I want full neigborship between r1 & r2 , without IGP & Static Routes , You have option of only BGP ?? Answer We Got :- Anivaldo Malungo Key point being there is that this is a wrong scenario to begin with. What u are trying to do will cause what we call "BGP Race Condition". U are trying to form iBGP peering using loopback as the source for open message and at the same time u are also advertise these loopbacks in the BGP process. Even if u were to advertise these loopbacks in the IGP/Static and they are still in the BGP process, u will end up in BGP flapping situation. U…
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