OSPF operational state Down state No hello packets received Router sends hello packets Transition to init state Init state Hello packets are received from the neighbor They contain the router ID of the sending router Transition to Two-Way state Two-Way State Communication between 2 routers is bidirectional The router elect DR and BDR Transition to…More
Introductions of OSPF
OSPF OSPFv3 is used for IPv6 networks. OSPF is a link state routing protocol A link is an interface on a router Link-state information includes the network prefix, prefix length and cost Components of OSPF Routing Protocol Messages Hello packet Database description packet Link-state request packet Link-state update packet Link-state acknowledgment packet Data structures Adjacency…More
FHRP(First Hop Redundantcy Protocol)
FHRP (First Hop Redundancy Protocols) Implement router redundancy, multiple routers are configured to work together to present the illusion of a single router. By sharing an IP address and a MAC address, two or more routers can act as a single virtual router. The ability of a network to dynamically recover from the failure of…More
Configuration of DHCPv6
DHCPv6 (Dynamic Host Configuration version 6) and SLAAC (Stateless Address Auto Configuration) The host will use 1 of the 3 methods defined by the ICMPv6 RA(Router Advertisement) message received on the interface to obtain the IPv6 address automatically. The Link Local address will be created automatically when the host boots and the interface is active.…More
Introductions of DHCPv4
DHCPv4 (Dynamic Host Configuration Protocol version 4) Steps to obtain a lease (DORA) Discover Broadcast with client’s MAC address to find the DHCP server Offer When the server receives the Discover message, it reserves an available IP address for the requesting client. Create an entry consisting of the MAC address of requesting client and the…More
EtherChannel protocols and configurations
EtherChannel Implementation restrictions Interface types can not be mixed. (Fast Ethernet and Gigabit Ethernet) Maximum interfaces in one logic link = 8 active physical interfaces = 16 physical interfaces Maximum logic links = 6 logic links on one switch The configuration of the both side physical ports should be the same. AutoNegotiation Protocols PAgp (Port…More