异步传输模式 (ATM) : IP over ATM

为什么无法ping通ATM接口?

2016 年 10 月 24 日 - 机器翻译
其他版本: PDFpdf | 英语 (2015 年 8 月 22 日) | 反馈


目录


简介

本文说明需要配置虚拟路径标识符(VPI)和虚拟信道标识符(VCI)在一个本地ATM接口为了顺利地ping它。

应用IP地址对ATM接口配置接口是路由的IP接口。为了使工作的ping,也请配置永久虚拟电路(PVC),因此路由器通过发送ATM信元的哪个虚拟电路知道。没有VC,路由器报告封装故障,如果调试指令启用。由封装,路由器是指在ping信息包附近包裹的Layer2 (L2)报头。

当您ping本地接口时, ATM信元在物理电线实际上被派出。如果端到端电路是活跃的, ping信元到远程路由器末端传播然后反向循环。交替地,请沿路径配置硬件或软件环回某处,包括在本地接口。请使用loopback diagnostic命令配置软件环回。

因为ATM VC点到点,请考虑关于您配置VC接口的种类的下列问题:

  • 主接口—支持多个VC。每个VC需要任一匹配本地PVC值对远程IP地址的静态或动态映射。没有映射,路由器将汇报封装与启用的调试的失败的错误消息。

  • 多点子接口—支持多个VC。每个VC需要任一匹配本地PVC值对远程IP地址的静态或动态映射。没有映射,路由器将汇报封装与启用的调试的失败的错误消息。

  • 点对点子接口—支持单个VC。因为路由器根据定义假设有单个设备在VC的另一端,明确映射没有要求。反而,路由器转发数据包根据路由决策的VC。换句话说,路由表告诉路由器IP数据包的下一跳是VC的远程终端。

先决条件

要求

本文档没有任何特定的要求。

使用的组件

本文档不限于特定的软件和硬件版本。

规则

有关文档规则的详细信息,请参阅 Cisco 技术提示规则

主要 接口

下表说明ping的本地接口必要的配置命令根据是否点到点或多点。

请勿配置IP地址和在主要ATM接口的仅VPI/VCI
!
interface ATM4/0
 ip address 10.1.1.1 255.255.255.0
 no ip directed-broadcast
 no atm ilmi-keepalive
!
cs-7204-15a#show atm vc
               VCD /                                     Peak Avg/Min Burst
Interface      Name         VPI   VCI  Type   Encaps     Kbps   Kbps  Cells Sts
cs-7204-15a#show atm map


cs-7204-15a#ping 10.1.1.1
 
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:
 
4w2d: IP: s=10.1.1.1 (local), d=10.1.1.1 (ATM4/0), len 100, sending
4w2d: IP: s=10.1.1.1 (local), d=10.1.1.1 (ATM4/0), len 100, encapsulation failed

!--- Router reports encapsulation failure messages because there is no VPI/VCI
!--- on which to send the packet.

配置在主要ATM接口的PVC
interface ATM4/0
 ip address 10.1.1.1 255.255.255.0
 no ip directed-broadcast
 no atm ilmi-keepalive
 pvc 1/32 
  encapsulation aal5snap
cs-7204-15a#show atm vc
               VCD /                                     Peak Avg/Min Burst
Interface      Name         VPI   VCI  Type   Encaps     Kbps   Kbps  Cells Sts
4/0            4              1    32   PVC    SNAP     149760                UP
cs-7204-15a#show atm map
cs-7204-15a#
debug ip packet

IP packet debugging is on
cs-7204-15a#ping 10.1.1.1
 
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:
 
4w2d: IP: s=10.1.1.1 (local), d=10.1.1.1 (ATM4/0), len 100, sending
4w2d: IP: s=10.1.1.1 (local), d=10.1.1.1 (ATM4/0), len 100, encapsulation failed

!--- Although this configures a PVC, either a dynamic or
!--- static mapping is still needed between the L2 and Layer 3 (L3) addresses.

配置在PVC的一个静态映射语句
interface ATM4/0
 ip address 10.1.1.1 255.255.255.0
 no ip directed-broadcast
 no atm ilmi-keepalive
 pvc 1/32 
  protocol ip 10.1.1.1
  
!--- This configures a static map back to the local interface. 
!--- Normally, the map statement points to the remote IP address.

  encapsulation aal5snap
cs-7204-15a#show atm map  
Map list ATM4/0pvc4 : PERMANENT
ip 10.1.1.1 maps to VC 4, VPI 1, VCI 32, ATM4/0
cs-7204-15a#ping 10.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:
5w1d: IP: s=10.1.1.1 (local), d=10.1.1.1 (ATM4/0), len 100, sending.
5w1d: IP: s=10.1.1.1 (local), d=10.1.1.1 (ATM4/0), len 100, sending.

!--- The router now sends the packets. However, since there is not a
!--- remote end in the lab setup, the pings fail.

配置在主接口的Loopback Diagnostic
interface ATM4/0
 ip address 10.1.1.1 255.255.255.0
 no ip directed-broadcast
 loopback diagnostic
 
!--- This configures a software loopback with the loopback diag command.

 no atm ilmi-keepalive
 pvc 1/32 
  protocol ip 10.1.1.1
  encapsulation aal5snap
cs-7204-15a#show atm map  

Map list ATM4/0pvc4 : PERMANENT
ip 10.1.1.1 maps to VC 4, VPI 1, VCI 32, ATM4/0
cs-7204-15a#ping 10.1.1.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
cs-7204-15a#
5w1d: IP: s=10.1.1.1 (local), d=10.1.1.1 (ATM4/0), len 100, sending
5w1d: IP: s=10.1.1.1 (ATM4/0), d=10.1.1.1 (ATM4/0), len 100, rcvd 3
5w1d: IP: s=10.1.1.1 (local), d=10.1.1.1 (ATM4/0), len 100, sending
5w1d: IP: s=10.1.1.1 (ATM4/0), d=10.1.1.1 (ATM4/0), len 100, rcvd 3

!--- The pings are successful. Note that the local interface both
!--- receives its own Internet Control Message Protocol (ICMP) echo and echo-reply.

多点子接口

配置ATM多点接口
interface ATM4/0
 no ip address
 no ip directed-broadcast
 loopback diagnostic
 no atm ilmi-keepalive
!
interface ATM4/0.1 multipoint
 ip address 10.1.1.1 255.255.255.0
 no ip directed-broadcast
 pvc 1/32 
  protocol ip 10.1.1.1
  
!--- This configures a static map or use inverse Address Resolution Protocol (ARP) on a multipoint subinterface.

  encapsulation aal5snap
cs-7204-15a#show atm map 

Map list ATM4/0.1pvc5 : PERMANENT
ip 10.1.1.1 maps to VC 5, VPI 1, VCI 32, ATM4/0.1
cs-7204-15a#ping 10.1.1.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
cs-7204-15a#
5w1d: IP: s=10.1.1.1 (local), d=10.1.1.1 (ATM4/0.1), len 100, sending
5w1d: IP: s=10.1.1.1 (ATM4/0.1), d=10.1.1.1 (ATM4/0.1), len 100, rcvd 3
5w1d: IP: s=10.1.1.1 (local), d=10.1.1.1 (ATM4/0.1), len 100, sending
5w1d: IP: s=10.1.1.1 (ATM4/0.1), d=10.1.1.1 (ATM4/0.1), len 100, rcvd 3

点对点子接口

点对点子接口
interface ATM4/0
 no ip address
 no ip directed-broadcast
 loopback diagnostic
 
!--- Use the loopback diagnostic command if
!--- the PVC is not configured end to end.

 no atm ilmi-keepalive
!
interface ATM4/0.2 point-to-point
 ip address 10.1.1.1 255.255.255.0
 no ip directed-broadcast
 pvc 1/32 
  encapsulation aal5snap
 
!--- Point-to-point interfaces do not need a static mapping or inverse ARP.

cs-7204-15a#show atm map


cs-7204-15a#ping 10.1.1.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
cs-7204-15a#
00:11:03: IP: s=10.1.1.1 (local), d=10.1.1.1 (ATM4/0.2), len 100, sending
00:11:03: IP: s=10.1.1.1 (ATM4/0.2), d=10.1.1.1 (ATM4/0.2), len 100, rcvd 3
00:11:03: IP: s=10.1.1.1 (local), d=10.1.1.1 (ATM4/0.2), len 100, sending
00:11:03: IP: s=10.1.1.1 (ATM4/0.2), d=10.1.1.1 (ATM4/0.2), len 100, rcvd 3


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Document ID: 10486