3C Flashcards
As discussed earlier, routing involves two basic activities: determination of optimal routing paths (____ ____) and the transport of packets through an internetwork (___ ___).
Path Determination
Packet Switching
Routers use routing tables to determine the best path. Routers populate their routing tables by learning paths to network destinations. The paths can be learned from ____ routes, ____ routes or ____ routes.
static, default or dynamic
Routers chose the path with the lowest ____ ____ (AD) when they know about multiple paths to the same destination from more than one routing source.
Administrative Distance (AD)
Static routes are manually configured by the system administrator as the ____ path to the destination.
only
Static routes are useful for controlling what?
They are useful for controlling security and reducing traffic.
Static routes are basically nothing more than ____ ____ entries established by the network administrator prior to the beginning of routing.
router table
____ ____ entries do not change unless the network administrator alters them.
Static route
Static routes are simple to configure and work well in environments where network traffic is relatively predictable and where network design is relatively simple. However, because static routing systems cannot react to network changes, they generally are considered ____ for today’s large, diverse networks.
unsuitable
Routers know about networks that are directly connected to them if their _____ are functional.
interfaces
When configuring static routes, look for paths that are not directly connected to the router that you want to be part of a path from source to destination. These routes are added to the routing table as ____ ____ reachable.
network destinations
A ___ ____ is a special static route manually defined by the system administrator as the path to take when no route to the destination is known.
default route
A default route, often called the ____ ____ ____ _____,
is a route to which all non-routable packets are sent.
gateway of last resort
___-____ is defined as a network that is not listed in a router’s routing table.
Non-routable
A ____ ____ is a Network Layer protocol that exchanges information packets with other internetwork routers to build and maintain a routing table.
routing protocol
Most of the dominant routing algorithms used today are dynamic routing algorithms such as…?
such as RIP, IGRP, OSPF, EIGRP, and BGP.
What metrics are involved in routing algorithms?
- Path Length
- Reliability
- Delay
- Bandwidth
- Load
- Communication cost
___ ____ is the most common routing metric used in routing algorithms.
Path length
The following describes which routing metric?
Some routing protocols allow network administrators to assign arbitrary costs to each network link. In this case, ___ ____ is the sum of the costs associated with each link traversed. Other routing protocols define hop count as a metric that specifies the number of passes (hops) through internetworking devices, such as routers, that a packet must take from a source to a destination.
path length
The following describes which routing metric?
In the context of routing algorithms, refers to the dependability (usually described in terms of the bit-error rate) of each network link. Some network links might go down more often than others. After a network fails, certain network links might be repaired more easily or more quickly than other links. Any reliability factors can be considered in the assignment of a reliability rating. These are arbitrary numeric values usually assigned to network links by network administrators
Reliability
The following describes which routing metric?
refers to the length of time required to move a packet from source to destination through the internetwork. ____ depends on many factors, including the bandwidth of intermediate network links, the port queues (information waiting to be processed) at each router along the way, network congestion on all intermediate network links, and the physical distance to be traveled. Because ____ is a conglomeration of several important variables, it is a common and useful metric.
Delay
The following describes which routing metric?
refers to the available traffic capacity of a link. All other things being equal, a 10Mbps Ethernet link would be preferable to a 64kbps leased line. Although ____ is a rating of the maximum attainable throughput on a link, routes through links with greater ____ do not necessarily provide better routes than routes through slower links. For example, if a faster link is busier, the actual time required to send a packet to the destination could be greater.
Bandwidth
The following describes which routing metric?
refers to the degree to which a network resource, such as a router, is busy. _____ can be calculated in a variety of ways, including CPU utilization and packets processed per second. Monitoring these parameters on a continual basis can be resource intensive.
Load
The following describes which routing metric?
Is another important metric especially because some organizations may not care about performance as much as they care about operating expenses. Even though line delay may be longer, they will send packets over their own lines rather than through the public lines that cost money for usage time. This metric, when used, is set by the Network Administrator.
Communication cost
Algorithms can be classified in several ways; however, we will focus on the two primary types of ____ ____ and ____ ____ algorithms
Distance Vector and Link State algorithms
