網(wǎng)絡(luò)工程師考試路由器方面相關(guān)知識(shí)

設(shè)置X.25的撥號(hào)備份,首先X.25連接的端口必須運(yùn)行動(dòng)態(tài)路由協(xié)議,異步撥號(hào)口必須使用靜態(tài)路由.本例選擇EIGRP作為路由選擇協(xié)議,將靜態(tài)路由的Metric的值設(shè)置為200,由于EIGRP的默認(rèn)Metric為90,所以當(dāng)同時(shí)有兩條路徑通往同一網(wǎng)段時(shí),其中Metric值小的路徑生效,而當(dāng)X.25連接出現(xiàn)問(wèn)題時(shí),路由器無(wú)法通過(guò)路由協(xié)議學(xué)習(xí)到路由表，則此時(shí)靜態(tài)路由生效，訪問(wèn)通過(guò)撥號(hào)端口實(shí)現(xiàn)。當(dāng)X.25連接恢復(fù)正常時(shí)，路由器又可以學(xué)習(xí)到路由表，則由于 Metric值的不同，靜態(tài)路由自動(dòng)被動(dòng)態(tài)路由所代替，這樣就實(shí)現(xiàn)了備份的功能。
路由器Router1配置如下:
hostname router1
!
enable secret 5 $1$UTvD$99YiY2XsRMxHudcYeHn.Y.
enable password cisco
!
username router2 password cisco
ip subnet-zero
chat-script cisco-default "" "AT" TIMEOUT 30 OK "ATDT \T" TIMEOUT 30 CONNECT \c
chat-script reset atz
interface Ethernet0
ip address 202.96.38.100 255.255.255.0
!
interface Serial0
ip address 202.96.0.1 255.255.255.0
encapsulation x25
x25 address 10112227
x25 htc 16
x25 map ip 202.96.0.2 10112225 broadcast
!
interface Serial1
no ip address
shutdown
!
!
interface Async 1
ip address 202.96.1.1 255.255.255.252
encapsulation ppp
dialer in-band
dialer idle-timeout 60
dialer map ip 202.96.1.2 name router2 modem-script cisco-default 2113470
dialer-group 1
ppp authentication chap
!
router eigrp 200
redistribute connected
network 202.96.0.0
!
ip route 202.96.37.0 255.255.255.0 202.96.1.2 200
dialer-list 1 protocol ip permit
line con 0
line aux 0
script dialer cisco-default
script reset reset
modem InOut
modem autoconfigure discovery
transport input all
rxspeed 38400
txspeed 38400
flowcontrol hardware
line vty 0 4
password cisco
login
!
end
路由器Router2配置如下:
hostname router2
!
enable secret 5 $1$T4IU$2cIqak8f/E4Ug6dLT0k.J0
enable password cisco
!
username router1 password cisco
ip subnet-zero
chat-script cisco-default "" "AT" TIMEOUT 30 OK "ATDT \T" TIMEOUT 30 CONNECT \c
chat-script reset atz
!
interface Ethernet0
ip address 202.96.37.100 255.255.255.0
!
interface Serial0
ip address 202.96.0.2 255.255.255.0
no ip mroute-cache
encapsulation x25
x25 address 10112225
x25 htc 16
x25 map ip 202.96.0.1 10112227 broadcast
!
interface Serial1
no ip address
shutdown
!
interface Async1
ip address 202.96.1.2 255.255.255.252
encapsulation ppp
keepalive 30
async default routing
async mode dedicated
dialer in-band
dialer idle-timeout 60
dialer wait-for-carrier-time 120
dialer map ip 202.96.1.1 name router1 modem-script cisco-default 2113469
dialer-group 1
ppp authentication chap
!
router eigrp 200
redistribute static
network 202.96.0.0
!
no ip classless
ip route 202.96.38.0 255.255.255.0 202.96.1.1 200
dialer-list 1 protocol ip permit
!
line con 0
exec-timeout 0 0
line aux 0
script reset reset
modem InOut
modem autoconfigure discovery
transport input all
rxspeed 38400
txspeed 38400
flowcontrol hardware
line vty 0 4
password cisco
login
!
end
CISCO路由器配置手冊(cè)－第三章（路由協(xié)議設(shè)置：RIP協(xié)議）
一、RIP協(xié)議
　
RIP(Routing information Protocol)是應(yīng)用較早、使用較普遍的內(nèi)部網(wǎng)關(guān)協(xié)議(Interior Gateway Protocol,簡(jiǎn)稱(chēng)IGP)，適用于小型同類(lèi)網(wǎng)絡(luò)，是典型的距離向量(distance-vector)協(xié)議。文檔見(jiàn)RFC1058、RFC1723。
RIP通過(guò)廣播UDP報(bào)文來(lái)交換路由信息，每30秒發(fā)送一次路由信息更新。RIP提供跳躍計(jì)數(shù)(hop count)作為尺度來(lái)衡量路由距離，跳躍計(jì)數(shù)是一個(gè)包到達(dá)目標(biāo)所必須經(jīng)過(guò)的路由器的數(shù)目。如果到相同目標(biāo)有二個(gè)不等速或不同帶寬的路由器，但跳躍計(jì)數(shù)相同，則RIP認(rèn)為兩個(gè)路由是等距離的。RIP最多支持的跳數(shù)為15，即在源和目的網(wǎng)間所要經(jīng)過(guò)的最多路由器的數(shù)目為15，跳數(shù)16表示不可達(dá)。
1. 有關(guān)命令
任務(wù)
命令
指定使用RIP協(xié)議
router rip
指定RIP版本
version {1|2}1
指定與該路由器相連的網(wǎng)絡(luò)
network network
注：1.Cisco的RIP版本2支持驗(yàn)證、密鑰管理、路由匯總、無(wú)類(lèi)域間路由(CIDR)和變長(zhǎng)子網(wǎng)掩碼(VLSMs)
2. 舉例
Router1:
router rip
version 2
network 192.200.10.0
network 192.20.10.0
！
相關(guān)調(diào)試命令：
show ip protocol
show ip route