5.2 Flashcards
(29 cards)
What’s distance vector?
Router algorithm prioritizes routes by # of hops
What is link state for Router algorithm?
Makes path by creating map and finding best path
What is convergence?
Process for routers to agree on network topology dynamically
What is a sinkhole?
Packet discarded without notification back to source.
What is a loop?
Packet forwarded around network until TTL expires
What is a route flap?
Interface going on and off rapidly
Can cause convergence problems
What is an Autonomous System?
Network controlled by one owner?
What does Interior Gateway Protocol do?
ID’s routes within the Autonomous System.
What does an Exterior Gateway Protocol do?
Advertise routes between Autonomous Systems
What is a RIP for?
Routing Info Protocol is a Distance Vector Routing Protocol (legacy)
[Helps select optimal path every 30 seconds with TTL of 15]
What is IGRP for?
Enhanced Interior Gateway Routing Protocol - Cisco
Routing Protocol for routing within domain or Autonomous System
[No Classless Addressing]
[Replaced by EIGRP]
How does EIGRP work?
Distance Vector Protocol
Hops AND 2 more factors
Bandwidth and Delay
What does Bandwidth and Delay do for Routing Protocols?
Calculates speed based on by bandwidth
Calculates speed based on time for packet to traverse links
How does RIP work vs EIGRP?
RIP = Updates every 30 sec [15 hops]
EIGRP = Only updates during topology change [255 hops]
How is EIGRP categorized?
Protocol # 88 in IP Header.
Is a Default IP Protocol. Doesn’t use TCP or UDP.
How does Link State algorithm work?
Are they cheaper or expensive?
Allows routers to store network topology and assess best routes
Small frequent neighbor updates to analyze network
Multicast protocol 89
.
Expensive. Require cpu/ram.
Is OSPF Link State or Vector Protocol?
When should you use OSPF?
Link State
Large orgs with multiple redundant networks
What is a Area Border Router?
Router that connects to multiple areas
What’s different from OSPF vs EIGRP?
OSPF is hierarchical. EIGRP is a flat system.
What is a backbone? What is it called?
Area 0.
Collection of border routers.
What is BGP for?
Border Gateway Protocol used between ISPs
.
EIGRP/OSPF are for Routers in a Domain.
BGP is for between Domains
What is NLRI?
Network Layer Reachability Information.
Classless network prefixes within BGP
.
Path selection on TTL, weight, local pref, origin, community
Will routers prefer routes with longer or shorter prefixes?
198.51.100.0/24 g0
198.51.100.0/28 g1
Longer
198.51.100.0/28 g1 will be chosen
What does AD value mean?
What AD values are these?
0 & 1
Administrative Distance value. (relative trustworthiness of route)
0 = Local Interface / Directly Connected
1 = Static Route
