IP Routing Flashcards
What is a router on a stick consisted of
A layer 2 switch which cannot route information with separate vlans out of different ports, so it is connected to a router via a trunk port to be able to route between vlans
What is a SVI & routed port
With a layer 3 switch, you have a virtual interface (with ip address) for each VLAN, which represents all ports that belong to the VLAN so internal routing is possible, OR if you want a routed port, you assign a port on the switch to a router port and connect the switch to a router (assign an IP to the port)
What does SVI stand for
Switch Virtual Interface
What does OSPF stand for
Open shortest path first
What versions of OSPF are for IPv4 and IPv6
OSPFv2 only covers IPv4 while OSPFv3 covers IPv6
What is OSPF’s Admin Distance
110
What type of routing protocol is OSPF
Link State
What is characteristic of OSPF
Establishes adjacencies with other routers by sending Link State Advertisements to routers in an area, Constructs a link state database from link state advertisements
What does OSPF find the best path based on?
Cost, which is a function of bandwidth
How does a router send a packet down the right path
It attempts to inject the best path into an IP routing table (populates routing information table) to be injected into IP table
What is a neighbor
A neighbor is a router that reside on the same network link, exchange hello messages with one another BUT NOT NECESSARY Link State Advertisements
What is an adjacency
An adjacency are routers that are neighbors, have exchanged Link State Updates and Data Description Packets; Only adjacencies construct a link state database
What does each OSPF topology have?
Area 0, a backbone area, or 0.0.0.0
What’s the requirement for having multiple areas in the OSPF model?
Each non-backbone area should connect to the backbone area.
What are routers with interfaces in more than one area called
Area Border Router (ABR)
What is one way that Cisco does not recommend but can allow you to directly connect any non-backbone area to a backbone area
Establish a virtual link between the two areas
What is one way that Cisco does not recommend but can allow you to directly connect any non-backbone area to a backbone area
Establish a virtual link between the two Area Border Routers
How do you calculate cost of an OSPF route?
Cost = reference bandwidth / interface bandwidth
What is the default reference bandwidth?
100 Mbps
What happens if your OSPF cost is a decimal?
You round up to the next nearest number