对OSPF COST的理解
今天在做实验的时候发现一个问题：在进程1中引入直连type1，并在引入时改COST值，再在另一台路由器上的进程10中引入进程1的路由，并且是type1 ,这时在进程十中并没有最初引入的那个cost值，所以引发了对这个问题的思考，作了如下的实验:
R1-S0/6/0--------S0/6/0-R2-S0/6/1--------S0/6/1-R4
R1与R2在ospf 1 area 0 R2和R4在OSPF 10 area 0
思路：在R1上引入直连，在R2上查看同一进程，同一区域下引入路由的COST
在R2上引入OSPF 1 ,在R4上查看另一进程area0下最初引入直连那个网段的COST
引入直连和OSPF 10引入进程时又有三种方式：直接引入，引入后加入type 1（默认是type 2,他们的区别是type 2 把AS内的cost忽略不计）
结论1：
注：上表中二列三行更改为1563，做excel表时出错。
结论2：
结论三，跨进程后把外部来的路由全部看成是cost 为1，不管你最初有没有作cost的更改。
完整配置（用的是H3C模拟器，与真机相差无机）：
R1：
#
version 5.20, Alpha 1011
#
sysname R1
#
password-control login-attempt 3 exceed lock-time 120
#
undo voice vlan mac-address 00e0-bb00-0000
#
ipsec cpu-backup enable
#
undo cryptoengine enable
#
domain default enable system
#
vlan 1
#
domain system
access-limit disable
state active
idle-cut disable
self-service-url disable
#
acl number 2000
rule 0 permit source 192.168.1.0 0.0.0.255
acl number 2001
rule 0 permit source 172.16.1.0 0.0.0.255
#
interface Serial0/6/0
link-protocol ppp
ip address 10.1.1.1 255.255.255.0
#
interface Serial0/6/1
link-protocol ppp
#
interface Serial0/6/2
link-protocol ppp
#
interface Serial0/6/3
link-protocol ppp
#
interface NULL0
#
interface LoopBack0
ip address 192.168.1.1 255.255.255.255
#
interface LoopBack1
ip address 172.16.1.1 255.255.255.255
#
interface Ethernet0/4/0
port link-mode bridge
#
interface Ethernet0/4/1
port link-mode bridge
#
interface Ethernet0/4/2
port link-mode bridge
#
interface Ethernet0/4/3
port link-mode bridge
#
interface Ethernet0/4/4
port link-mode bridge
#
interface Ethernet0/4/5
port link-mode bridge
#
interface Ethernet0/4/6
port link-mode bridge
#
interface Ethernet0/4/7
port link-mode bridge
#
ospf 1
import-route direct type 1 route-policy test
area 0.0.0.0
network 10.1.1.0 0.0.0.255
#
route-policy test permit node 10
if-match acl 2000
apply cost 1000
route-policy test permit node 20
if-match acl 2001
apply cost 500
#
load xml-configuration
#
user-interface con 0
user-interface vty 0 4
#
return
R2:
version 5.20, Alpha 1011
#
sysname R2
#
password-control login-attempt 3 exceed lock-time 120
#
undo voice vlan mac-address 00e0-bb00-0000
#
ipsec cpu-backup enable
#
undo cryptoengine enable
#
domain default enable system
#
vlan 1
#
domain system
access-limit disable
state active
idle-cut disable
self-service-url disable
#
acl number 2000
rule 0 permit source 192.168.1.0 0.0.0.255
acl number 2001
rule 0 permit source 172.16.1.0 0.0.0.255
#
interface Serial0/6/0
link-protocol ppp
ip address 10.1.1.2 255.255.255.0
#
interface Serial0/6/1
link-protocol ppp
ip address 10.1.2.1 255.255.255.0
#
interface Serial0/6/2
link-protocol ppp
#
interface Serial0/6/3
link-protocol ppp
#
interface NULL0
#
interface Ethernet0/4/0
port link-mode bridge
#
interface Ethernet0/4/1
port link-mode bridge
#
-----------------------------------------------------------------
R4：
sysname R4
#
password-control login-attempt 3 exceed lock-time 120
#
undo voice vlan mac-address 00e0-bb00-0000
#
ipsec cpu-backup enable
#
undo cryptoengine enable
#
domain default enable system
#
vlan 1
#
domain system
access-limit disable
state active
idle-cut disable
self-service-url disable
#
interface Serial0/6/0
link-protocol ppp
#
interface Serial0/6/1
link-protocol ppp
ip address 10.1.2.2 255.255.255.0
#
interface Serial0/6/2
link-protocol ppp
#
interface Serial0/6/3
link-protocol ppp
#
interface NULL0
#
interface LoopBack0
ip address 192.168.2.1 255.255.255.255
#
interface LoopBack1
ip address 172.16.2.1 255.255.255.255
#
interface Ethernet0/4/0
port link-mode bridge
#
interface Ethernet0/4/1
port link-mode bridge
#
interface Ethernet0/4/2
port link-mode bridge
#
interface Ethernet0/4/3
port link-mode bridge
#
interface Ethernet0/4/4
port link-mode bridge
#
interface Ethernet0/4/5
port link-mode bridge
#
interface Ethernet0/4/6
port link-mode bridge
#
interface Ethernet0/4/7
port link-mode bridge
#
ospf 10
area 0.0.0.0
network 10.1.2.0 0.0.0.255
#
load xml-configuration
#
user-interface con 0
user-interface vty 0 4
#
return
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