HSRP, VRRP, and GLBP
basics of NTP
There are a few different types of transmission methods for IP packets with the most common being unicast. A Unicast packet, is a packet that is sent from a single source to a single destination. Most traffic on modern networks would be unicast. Another transmission method for IP packets, is broadcast. A Broadcast message is sent from a single source, to everywhere. Each device on the IP network within that subnet will receive a broadcast packet. An example of a broadcast is a DHCP request packet.
In my previous article, I went through the fundamentals of BGP and the basic configuration of configuring BGP peers and advertising networks. In this article I will delve a little into just how powerful BGP route manipulation can be. First, let's take a look at the 4 typical redundancy scenarios that an organisation might use to establish their connection to their Internet Service Provider.
In the previous article, I talked a little about BGP and how it works. This article will go through the configuration BGP using both IPv4 and IPv6 addressing. For this article, I will use the following topology.
BGP (Border Gateway Protocol) is the protocol of the Internet. BGP is designed to handle hundreds of thousands of routes unlike our IGP counterparts. Currently there are roughly 635 000 IPv4 routes on the internet. Could you imagine an IGP like OSPF running on an Internet router containing 635k routes? It would die if a link flapped. This is why BGP was created. Actually, there was an Internet routing protocol called EGP (Exterior Gateway Protocol) which was BGP's predecessor however it was replaced by BGP a long time ago.
OSPFv3 is the updated version of OSPFv2 that has support for IPv6 addressing as well as IPv4. OSPFv3 is defined in RFC 5340. OSPFv3 differs to OSPFv2 in the following ways:
Okay, so now let's talk about how to configure OSPF. Configuring OSPF is just like configuring any other dynamic routing protocol. You first need to enable OSPF by configuring the OSPF process ID by using the global configuration command router ospf <process-id>. Once you have configured the OSPF Process ID, it is best practice to manually configure the OSPF Router ID using the router ospf configuration subcommand router-id <id>.