Requirements for Fast Ether Channel

• All ports part of FEC must be set to the same speed.

• All ports must belong to the same VLAN.

• Duplex must be the same (half or full), not a mixture.

• Up to eight ports can be bundled together.

• To set FastEther channel on a switch, the CatOS syntax is set port channel.

• To set FastEther channel on a router, the IOS syntax is channel-group under the Fast Ethernet interface.

Table 2-19 The States of Spanning Tree

Bridge Port State

Description

Disabled

The port is not participating in spanning tree and is not active.

Listening

The port has received data from the interface and will listen for frames. In this state, the bridge receives only data but does not forward any frames to the interface or to other ports.

Learning

In this state, the bridge still discards incoming frames. The source address associated with the port is added to the CAM table. BPDU are sent and received.

Forwarding

The port is fully operational; frames are sent and received.

Blocking

The port has been through the learning and listening states, and because this particular port is a dual path to the root bridge, the port is blocked to maintain a loop-free topology.

Table 2-20 Class A, B, C, D, and E Ranges

Class of Address

Starting Bit Pattern

Range

Default Subnet Mask

Class A

Oxxxxxxx

1 to 126, 127*

255.0.0.0

Class B

10xxxxxx

128 to 191

255.255.0.0

Class C

110xxxxx

192 to 223

255.255.255.0

Class D (multicast)

1110xxxx

224 to 239

255.255.255.240

Class E

1111xxxx

240 to 255

Reserved

127.0.0.0 is reserved for loopbacks. Other reserved addresses for private use as defined by RFC 1918 are as follows:

172.16.0.0-172.31.255.255

192.168.0.0-192.168.255.255

Table 2-21 Routing Protocol Classifications

Routing Protocol

Class

IGRP

Distance vector (classful)

EIGRP

Hybrid (classless)

OSPF

Link-state (classless)

RIPv1

Distance vector (classful)

RIPv2

Distance vector (classless)

BGP

Path vector (classless)

Table 2-22 TCP Flags Summary

Flag

Description

URG (U)

Urgent—Informs the other station that urgent data is being carried. The receiver will decide what do with the data.

ACK (A)

Acknowledge—Indicates that the packet is an acknowledgment of received data, and the acknowledgment number is valid.

PSH (P)

Push—Informs the end station to send data to the application layer immediately.

RST (R)

Reset—Resets an existing connection.

SYN (S)

Synchronize—Initiates a connection, commonly known as established.

FIN (F)

Finished—Indicates that the sender is finished sending data and terminates the session.

Table 2-23 TCP/IP Applications

Application

Description

Address Resolution Protocol (ARP)

ARP maps an IP address to a MAC address.

Reverse Address Resolution Protocol (RARP)

RARP determines a host's IP address when the MAC address is known.

Dynamic Host Configuration Protocol (DHCP)

Dynamically provides IP addresses to TCP/IP hosts, subnet masks, and gateway addressing. Many other IP options can be assigned, as well.

Hot Standby Router Protocol (HSRP)

Redundancy gateway protocol, Cisco proprietary.

Internet Control Message Protocol (ICMP)

A network layer (Layer 3) Internet protocol that reports errors and provides other information relevant to IP packet processing. ICMP is fully documented in RFC 792.

Telnet

TCP/IP application layer protocol that enables remote management of TCP/IP hosts, such as routers or switches.

File Transfer Protocol (FTP)

TCP/IP application layer protocol that enables file transfer between TCP/IP hosts using a TCP, connection-orientated protocol.

Trivial File Transfer Protocol (TFTP)

TCP/IP application layer protocol that enables file transfers between TCP/IP hosts using a UDP, connectionless protocol.

Table 2-24 Default Administrative Distances

Route Source

Default Distance

Connected interface

0

Static route

1

Enhanced IGRP summary route

5

External BGP

20

Internal enhanced IGRP

90

IGRP

100

OSPF

110

IS-IS

115

RIP

120

EGP

140

EIGRP external route

170

Internal BGP

200

Unknown

255

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