正做一个项目，五路信号从卫星下来通过RS232线缆接到cisco3640上的8A/S模块口上，有四路正常，但有一路的line procotol先up了，过1分零8s后，就down，再过12s后up，如此反复，先怀疑是端口问题，换了n个s端口，问题依旧，再怀疑是卫星信号问题，但换一台2611做就正常了，设置应该没有问题，因为五路是一样的设置，哪位高手能指点一下，感激不尽啊

能贴一下两边的配置么？

硬件是同一个NM-8A/S么？

怪了？
36和26多数模块通用，你换到2611上的还是原模块么？连接线缆和设备相同么？
你将故障的哪个口子的线插到好的口子上，原好的口子是否也故障？

是啊。最好自己仔细查一下。“完全一样”需要I再自己核实一下。

路由器配置如下：

LFMPRTR6#sh run
Building configuration...

Current configuration : 2456 bytes
!
version 12.2
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname LFMPRTR6
!
logging queue-limit 100
enable secret 5 $1$PGon$BdViUFLOsvqVy2aFaZVRK.
enable password ws90a3kjs90? ><
!
ip subnet-zero
!
!
no ip domain-lookup
!
call rsvp-sync
!
!
!
!
!
!
controller E1 0/0
!
!
!
interface Serial1/0
description VAST To SeBei
ip address 192.168.1.1 255.255.255.0
shutdown
fair-queue
!
interface Serial1/1
description VAST To DeLingHa
ip address 192.168.8.1 255.255.255.0
!
interface Serial1/2
description VAST To XiNing
ip address 192.168.2.1 255.255.255.0
!
interface Serial1/3
description VAST To MinHe
ip address 192.168.3.1 255.255.255.0
!
interface Serial1/4
description VAST To LanZhou
ip address 192.168.4.1 255.255.255.0
!
interface Serial1/5
description To LanZhou center Router(center)
ip address 192.168.20.1 255.255.255.0
clockrate 64000
!
interface Serial1/6
no ip address
shutdown
!
interface Serial1/7
ip address 192.168.1.1 255.255.255.0
shutdown
ignore-dcd
!
interface Serial2/0
ip address 192.168.1.1 255.255.255.0
!
interface Serial2/1
ip address 192.168.1.45 255.255.255.0
!
interface Serial2/2
ip address 192.168.1.46 255.255.255.0
!
interface Serial2/3
no ip address
shutdown
!
interface Serial2/4
no ip address
shutdown
!
interface Serial2/5
no ip address
shutdown
!
interface Serial2/6
no ip address
shutdown
!
interface Serial2/7
no ip address
shutdown
!
interface FastEthernet3/0
ip address 128.192.1.68 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet3/1
ip address 128.192.2.68 255.255.255.0
duplex auto
speed auto
!
router rip
network 192.168.20.0
!
ip classless
ip route 10.0.0.0 255.255.255.0 192.168.20.2
ip route 10.0.1.0 255.255.255.0 192.168.20.2
ip route 200.0.1.0 255.255.255.0 192.168.1.2
ip route 200.0.2.0 255.255.255.0 192.168.2.2
ip route 200.0.3.0 255.255.255.0 192.168.3.2
ip route 200.0.4.0 255.255.255.0 192.168.4.2
ip route 200.0.5.0 255.255.255.0 128.192.1.67
ip route 200.0.5.0 255.255.255.0 128.192.2.67
ip route 200.0.6.0 255.255.255.0 128.192.1.67
ip route 200.0.6.0 255.255.255.0 128.192.2.67
ip route 200.0.7.0 255.255.255.0 128.192.1.67
ip route 200.0.7.0 255.255.255.0 128.192.2.67
ip route 200.0.8.0 255.255.255.0 192.168.8.2
ip http server
!
!
dial-peer cor custom
!
!
!
!
line con 0
line aux 0
line vty 0
password qitrj887
login
line vty 1 4
login
line vty 5 129
login
line vty 130
password 3453kj8o8
login
!
end

我原来使用s1/0口那一路有问题，后来换了另外的口（配置中未加描述的都是），也是同样的问题，出现以下情况：
LFMPRTR6#
01:04:48: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial2/2, changed sta
te to down
01:05:00: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial2/2, changed sta
te to up
01:06:08: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial2/2, changed sta
te to down
01:06:20: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial2/2, changed sta
te to up

配置可以说都是一样的了，因为没有什么要写的，只是简单配一下ip而已，以前用两台路由器对接做实验出现过这个问题，那是因为clockrate只能在dce设备端设置的问题，但现在clockrate 是由卫星设备给出，跟路由器没有关系啊。