在Nexus上配置LISP多跳移动性

简介

本文档介绍在启用定位器身份分离协议(LISP)的网络中跨数据中心(DC)移动而无需更改其IP地址的IP设备的配置和验证。

先决条件

要求

思科建议您具备LISP的基本知识。

使用的组件

本文档不限于特定的软件和硬件版本。

本文档中的信息都是基于特定实验室环境中的设备编写的。本文档中使用的所有设备最初均采用原始（默认）配置。如果您使用的是真实网络，请确保您已经了解所有命令的潜在影响。

背景信息

在LISP环境中，此设备称为动态终端标识符(EID)。LISP多跳移动性支持子网扩展模式，该模式允许不同DC拥有相同的子网，而子网又允许虚拟机(VM)在迁移到另一DC时保留其分配的IP地址。

第一跳路由器(FHR)检测动态EID的存在，并通过EID通知消息通知xTR端网关。xTR注册动态EID以映射服务器，并对通过LISP域的流量执行LISP封装和解封功能。

部署在不同DC中的xTR必须通过数据中心互联(DCI)技术(如重叠传输虚拟化(OTV))进行连接。 在Nexus中，支持OTV组播模式。

配置

网络图

此图像用作文档其余部分的示例拓扑。

• xTR:LISP路由器可以是ITR或ETR，具体取决于流量方向。如果流量从LISP路由器流出，它将成为该流的ITR，而接收端LISP路由器将成为该路由器的ETR。

• ITR:入口隧道路由器

• ETR:出口隧道路由器

• 映射解析器(MR):映射解析器是LISP站点ITR在解析EID到RLOC映射时向其发送LISP映射请求查询的LISP基础设施设备。

• 映射服务器(MS):映射服务器是LISP站点ETR注册到其EID前缀的LISP基础设施设备。映射服务器将注册的EID前缀的聚合通告到LISP映射系统。所有LISP站点都使用LISP映射系统来解析EID到RLOC的映射。

• EID地址：EID地址包括标识终端的IP地址和前缀。通过解析EID到RLOC的映射，可实现LISP站点间的EID可达性。

• 路由定位器(RLOC)地址：RLOC地址包括标识IP网络中不同路由器的IP地址和前缀。RLOC空间内的可达性通过传统路由方法实现。

• SMR:征集 — 地图 — 请求；控制平面消息，用于通知远程xTR以更新它们缓存的映射。

• ASM:跨子网模式；允许在没有第2层扩展的情况下在LISP站点之间实现EID移动。

• 映射通知：检测到EID的xTR使用的LISP消息，以便更新同一LISP站点中有关该发现的其他xTR。映射服务器也使用它来确认已接收并处理映射寄存器。

• 映射注册：xTR用于向映射服务器注册EID的LISP消息。

在本文讨论的示例中，流量持续从VM(172.16.54.200)流向站点3(172.16.20.1)。

西区

第一跳路由器(FHR-1):

!
feature lisp
!
ip lisp etr
!
lisp dynamic-eid VM
  database-mapping 172.16.54.0/24 10.1.1.1 priority 10 weight 50
  database-mapping 172.16.54.0/24 10.2.2.2 priority 10 weight 50
  eid-notify 10.10.10.10 key 3 9125d59c18a9b015
  map-notify-group 225.1.1.1
!
interface loopback0
  ip address 10.1.1.1/32
  ip router ospf 1 area 0.0.0.0
!
interface Vlan2
  no shutdown
  lisp mobility VM
  lisp extended-subnet-mode
  ip address 172.16.54.3/24
  ip ospf passive-interface
  ip router ospf 1 area 0.0.0.0
  ip pim sparse-mode
  no ip arp gratuitous request
  hsrp 1
    preempt
    priority 120
    ip 172.16.54.1
!

FHR-2:

!
feature lisp
!
ip lisp etr
!
lisp dynamic-eid VM
  database-mapping 172.16.54.0/24 10.1.1.1 priority 10 weight 50
  database-mapping 172.16.54.0/24 10.2.2.2 priority 10 weight 50
  eid-notify 10.10.10.10 key 3 9125d59c18a9b015
  map-notify-group 225.1.1.1
!
interface Vlan2
  no shutdown
 lisp mobility VM
  lisp extended-subnet-mode
  ip address 172.16.54.2/24
  ip ospf passive-interface
  ip pim sparse-mode 
  no ip arp gratuitous request
  hsrp 1
    preempt
    priority 90
    ip 172.16.54.1
!
interface loopback0
  ip address 10.2.2.2/32
  ip router ospf 1 area 0.0.0.0

xTR:

!
feature lisp
!
ip lisp itr-etr
ip lisp database-mapping 172.16.54.0/24 10.10.10.10 priority 10 weight 50
ip lisp itr map-resolver 192.168.1.1
ip lisp etr map-server 192.168.1.1 key 3 9125d59c18a9b015
!
lisp dynamic-eid VM
  database-mapping 172.16.54.0/24 10.10.10.10 priority 10 weight 50
  eid-notify authentication-key 3 9125d59c18a9b015
!
interface loopback0
  ip address 10.10.10.10/32
  ip router ospf 1 area 0.0.0.0
!

东DC

FHR-3:

  

!
feature lisp
!
ip lisp etr
!
lisp dynamic-eid VM
  database-mapping 172.16.54.0/24 10.3.3.3 priority 10 weight 50
  database-mapping 172.16.54.0/24 10.4.4.4 priority 10 weight 50
  eid-notify 10.11.11.11 key 3 9125d59c18a9b015
  map-notify-group 225.1.1.1
!
interface Vlan2
  no shutdown
 lisp mobility VM
  lisp extended-subnet-mode
  ip address 172.16.54.4/24
  ip ospf passive-interface
  ip router ospf 1 area 0.0.0.0
  ip pim sparse-mode
  no ip arp gratuitous request
  hsrp 1
    preempt
    priority 110
    ip 172.16.54.1
!
interface loopback0
  ip address 10.3.3.3/32
  ip router ospf 1 area 0.0.0.0

FHR-4:

!
feature lisp
!
ip lisp etr
!
lisp dynamic-eid VM
  database-mapping 172.16.54.0/24 10.3.3.3 priority 10 weight 50
  database-mapping 172.16.54.0/24 10.4.4.4 priority 10 weight 50
  eid-notify 10.11.11.11 key 3 9125d59c18a9b015
 map-notify-group 225.1.1.1
!
interface Vlan2
  no shutdown
  lisp mobility VM
  lisp extended-subnet-mode
  ip pim sparse-mode 
  ip ospf passive-interface
  ip address 172.16.54.5/24
  hsrp 1
    preempt
    priority 90
    ip 172.16.54.1
!
interface loopback0
  ip address 10.4.4.4/32
  ip router ospf 1 area 0.0.0.0

xTR:

!
interface loopback0
  ip address 10.11.11.11/32
  ip router ospf 1 area 0.0.0.0
!
feature lisp
!
ip lisp itr-etr
ip lisp database-mapping 172.16.54.0/24 10.11.11.11 priority 10 weight 50
ip lisp itr map-resolver 192.168.1.1
ip lisp etr map-server 192.168.1.1 key 3 9125d59c18a9b015
!
lisp dynamic-eid VM
  database-mapping 172.16.54.0/24 10.11.11.11 priority 9 weight 50
  eid-notify authentication-key 3 9125d59c18a9b015
!

MS/MR

!
router lisp
 locator-table default
 site 1
  authentication-key cisco
  eid-prefix 172.16.54.0/24 accept-more-specifics
  exit
 !
 site 2
  authentication-key cisco
  eid-prefix 172.16.20.0/24 accept-more-specifics
  exit
 !
 ipv4 map-server
 ipv4 map-resolver

站点3

!
router lisp
 database-mapping 172.16.20.0/24 10.20.20.20 priority 10 weight 50
 ipv4 itr map-resolver 192.168.1.1
 ipv4 itr
 ipv4 etr map-server 192.168.1.1 key cisco
 ipv4 etr
 exit
!
interface Loopback1
 ip address 10.20.20.20 255.255.255.255
!
interface Loopback2
 ip address 172.16.20.1 255.255.255.0
!

运营顺序

步骤1.启动VM。

VM已打开电源，并已开始将流量发送到远程站点（即站点3）。FHR-1接收此流并创建动态EID:

N7K-358-West-FHR1# show lisp dynamic-eid summary
LISP Dynamic EID Summary for VRF "default"
* = Dyn-EID learned by site-based Map-Notify
! = Dyn-EID learned by routing protocol
^ = Dyn-EID learned by EID-Notify
Dyn-EID Name   Dynamic-EID      Interface     Uptime    Last      Pending
                                                        Packet    Ping Count
VM             172.16.54.200    Vlan2         06:50:21  00:12:12  0

N7K-358-West-FHR1# show lisp dynamic-eid detail
LISP Dynamic EID Information for VRF "default"
Dynamic-EID name: VM
  Database-mapping [0] EID-prefix: 172.16.54.0/24, LSBs: 0x00000003
    Locator: 10.1.1.1, priority: 10, weight: 50
             Uptime: 06:51:34, state: up, local
    Locator: 10.2.2.2, priority: 10, weight: 50
             Uptime: 06:50:10, state: up
  Registering more-specific dynamic-EIDs
  Registering routes: disabled
  Map-Server(s): none configured, use global Map-Server
  Site-based multicast Map-Notify group: 225.1.1.1
  Extended Subnet Mode configured on 1 interfaces
  Number of roaming dynamic-EIDs discovered: 3
  Last dynamic-EID discovered: 172.16.54.1, 00:00:04 ago
  Roaming dynamic-EIDs:
    172.16.54.200, Vlan2, uptime: 06:50:31, last activity: 00:12:22
      Discovered by: packet reception

步骤2. FHR安装LISP路由。

如步骤1所示，FHR在收到来自VM的数据包时创建动态EID条目。然后在路由信息库(RIB)中安装a/32路由：

N7K-358-FHR1-West-DC# show ip route 172.16.54.200
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

172.16.54.200/32, ubest/mbest: 1/0, attached
    *via 172.16.54.200, Vlan2, [240/0], 06:58:08, lisp, dyn-eid
     via 172.16.54.200, Vlan2, [250/0], 06:58:45, am

步骤3. FHR将此动态EID通知所有其他FHR。

此FHR将映射通知消息发送到所有其他FHR，这些FHR包括本地站点和所有远程站点中的FHR。在本例中，FHR-1将有关172.16.54.200的映射通知发送到本地DC上的FHR-2以及东DC上的FHR-3和FHR-4。

但是，只有本地站点FHR可以在其RIB中安装该EID的路由，如下所示：

N7K-358-FHR2-West-DC# show lisp dynamic-eid detail
LISP Dynamic EID Information for VRF "default"
Dynamic-EID name: VM
 Database-mapping [0] EID-prefix: 172.16.54.0/24, LSBs: 0x00000003
 Locator: 10.1.1.1, priority: 10, weight: 50
 Uptime: 00:01:04, state: up
 Locator: 10.2.2.2, priority: 10, weight: 50
 Uptime: 00:01:53, state: up, local
 Registering more-specific dynamic-EIDs
 Registering routes: disabled
 Map-Server(s): none configured, use global Map-Server
 Site-based multicast Map-Notify group: 225.1.1.1
 Extended Subnet Mode configured on 1 interfaces
 Number of roaming dynamic-EIDs discovered: 1
 Last dynamic-EID discovered: 172.16.54.200, 00:01:04 ago
 Roaming dynamic-EIDs:
172.16.54.200, Vlan2, uptime: 00:01:04, last activity: 00:00:42
 Discovered by: site-based Map-Notify
Secure-handoff pending for sources: none

N7K-358-FHR2-West-DC#sh ip route 172.16.54.200
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>
172.16.54.200/32, ubest/mbest: 1/0, attached
 *via 172.16.54.200, Vlan2, [240/0], 00:00:08, lisp, dyn-eid
 via 172.16.54.200, Vlan2, [250/0], 00:01:53, am

  

步骤4. FHR将此EID更新到本地xTR。

一旦FHR上的两个站点都知道EID，它就会通知其本地站点的xTR此使用EID通知消息的EID。

East DC xTR路由器也为此前缀安装空0路由，而West DC xTR在RIB中添加此前缀。

N7K-FA8-East_xTR#show ip route 172.16.54.200
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

172.16.54.200/32, ubest/mbest: 1/0, attached
    *via 172.16.54.200, Null0, [241/0], 00:00:32, lisp, dyn-eid

N7K-358-West_xTR#show lisp dynamic-eid detail
LISP Dynamic EID Information for VRF "default"
Dynamic-EID name: VM
 Database-mapping [0] EID-prefix: 172.16.54.0/24, LSBs: 0x00000001
 Locator: 10.10.10.10, priority: 10, weight: 50
 Uptime: 00:02:37, state: up, local
 Registering more-specific dynamic-EIDs
 Registering routes: disabled
 Map-Server(s): none configured, use global Map-Server
 Site-based multicast Map-Notify group: none configured
 Number of roaming dynamic-EIDs discovered: 1
 Last dynamic-EID discovered: 172.16.54.1, 00:00:06 ago
 Roaming dynamic-EIDs:
 172.16.54.200, (null), uptime: 00:00:28, last activity: 00:00:06
 Discovered by: EID-Notify
 EID-Notify Locators:
 10.1.1.1
 10.2.2.2

N7K-358-West_xTR#sh ip route 172.16.54.200
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>
172.16.54.0/24, ubest/mbest: 1/0
 via 10.10.13.3, Eth3/2, [110/44], 00:01:00, ospf-1, intra

本地xTR向MR/MS注册EID:

East DC xTR还向MR/MS发送映射注册消息，并向其注册新发现的EID。站点3路由器也是如此。

MS_MR#show lisp site 172.16.54.200/32
LISP Site Registration Information

Site name: 1
Allowed configured locators: any
Requested EID-prefix:
  EID-prefix: 172.16.54.200/32
    First registered:     07:11:28
    Routing table tag:    0
    Origin:               Dynamic, more specific of 172.16.54.0/24
    Merge active:         No
    Proxy reply:          No
    TTL:                  00:03:00
    State:                complete
    Registration errors:
      Authentication failures:   0
      Allowed locators mismatch: 0
    ETR 10.10.90.1, last registered 00:00:07, no proxy-reply, map-notify
                    TTL 00:03:00, no merge, hash-function sha1, nonce 0x00000000-0x00000000
                    state complete, no security-capability
                    xTR-ID N/A
                    site-ID N/A
      Locator      Local  State      Pri/Wgt  Scope
      10.10.10.10  yes    up          10/50   IPv4 none

MS_MR#sh lisp site 172.16.20.0/24
LISP Site Registration Information
Site name: 2
Allowed configured locators: any
Requested EID-prefix:
 EID-prefix: 172.16.20.0/24
 First registered: 06:30:48
 Routing table tag: 0
 Origin: Configuration, accepting more specifics
 Merge active: No
 Proxy reply: No
 TTL: 1d00h
 State: complete
 Registration errors:
 Authentication failures: 0
 Allowed locators mismatch: 0
 ETR 10.10.67.7, last registered 00:00:23, no proxy-reply, map-notify
 TTL 1d00h, no merge, hash-function sha1, nonce 0xEE339164-0xC3199AF1
 state complete, no security-capability
 xTR-ID 0x7C6C7CF6-0x2AE64A0C-0xDCBC62DA-0x79762795
 site-ID unspecified
 Locator Local State Pri/Wgt Scope
 10.20.20.20 yes up 10/50 IPv4 none

步骤5.检验站点1和站点3 xTR上的流量：

N7K-358-West_xTR# show ip lisp map-cache
LISP IP Mapping Cache for VRF "default" (iid 0), 3 entries
* = Locator data counters are cumulative across all EID-prefixes

0.0.0.0/1, uptime: 00:13:28, expires: 00:01:31, via map-reply
  Negative cache entry, action: forward-native

128.0.0.0/3, uptime: 00:13:28, expires: 00:01:31, via map-reply
  Negative cache entry, action: forward-native

172.16.20.0/24, uptime: 00:00:26, expires: 23:59:33, via map-reply, auth
  Locator      Uptime    State       Priority/  Data      Control       MTU
                                     Weight     in/out    in/out
  10.20.20.20  00:00:26  up          10/50      0/0*      0/0          1500

站点3 LISP映射缓存条目：

Site-3#show ip lisp map-cache
LISP IPv4 Mapping Cache for EID-table default (IID 0), 2 entries

0.0.0.0/0, uptime: 01:53:04, expires: never, via static send map-request
  Negative cache entry, action: send-map-request
172.16.54.200/32, uptime: 01:50:02, expires: 22:09:57, via map-reply, complete
  Locator      Uptime    State      Pri/Wgt
 10.10.10.10  01:50:02  up          10/50

步骤6. VM从West DC移至East DC。

在数据中心之间进行虚拟机迁移之前，请执行以下步骤。现在，VM从West DC移动到East DC，无需更改IP地址。当VM从West DC移动到East DC时，East DC的FHR-3从VM接收数据包，并将其IP地址添加到动态EID表。然后，它向包括West DC的所有FHR发送映射通知请求，并且一旦West DC收到映射通知请求，它会从动态EID表中删除VM条目，该EID表是当VM存在于West DC时创建的。West DC的xTR现在安装到VM IP的空0路由。

以下是FHR-3上Dynamic-EID在东DC的状态：

N7K-FA8-East_FHR3# sh lisp dynamic-eid detail
LISP Dynamic EID Information for VRF "default"
Dynamic-EID name: VM
  Database-mapping [0] EID-prefix: 172.16.54.0/24, LSBs: 0x00000003
    Locator: 10.3.3.3, priority: 10, weight: 50
             Uptime: 02:04:48, state: up, local
    Locator: 10.4.4.4, priority: 10, weight: 50
             Uptime: 02:03:27, state: up
  Registering more-specific dynamic-EIDs
  Registering routes: disabled
  Map-Server(s): none configured, use global Map-Server
  Site-based multicast Map-Notify group: 225.1.1.1
  Extended Subnet Mode configured on 1 interfaces
  Number of roaming dynamic-EIDs discovered: 1
  Last dynamic-EID discovered: 172.16.54.1, 00:00:14 ago
  Roaming dynamic-EIDs:
    172.16.54.200, Vlan2, uptime: 00:04:28, last activity: 00:03:11
      Discovered by: packet reception

N7K-FA8-East_FHR3# sh ip route 172.16.54.200
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

172.16.54.200/32, ubest/mbest: 1/0, attached
    *via 172.16.54.200, Vlan2, [240/0], 00:05:00, lisp, dyn-eid
     via 172.16.54.200, Vlan2, [250/0], 00:05:10, am

因此，West FHR没有VM的动态EID，即172.16.54.200:

N7K-358-West-FHR1(config)# sh lisp dynamic-eid summary
LISP Dynamic EID Summary for VRF "default"
* = Dyn-EID learned by site-based Map-Notify
! = Dyn-EID learned by routing protocol
^ = Dyn-EID learned by EID-Notify
Dyn-EID Name   Dynamic-EID      Interface     Uptime    Last      Pending
                                                        Packet    Ping Count
VM             172.16.54.2      Vlan2         00:33:30  00:00:07  0

步骤7. xTR at West DC在路由表中添加空0条目：

N7K-358-West_xTR# sh ip route 172.16.54.200
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

172.16.54.200/32, ubest/mbest: 1/0, attached
    *via 172.16.54.200, Null0, [241/0], 00:00:05, lisp, dyn-eid

步骤8. FHR-3通过EID通知更新East xTR，然后East xTR使用迁移的VM前缀向MS发送映射寄存器：

N7K-FA8-East_xTR(config)# show lisp dynamic-eid Detail
LISP Dynamic EID Information for VRF "default"
Dynamic-EID name: VM
  Database-mapping [0] EID-prefix: 172.16.54.0/24, LSBs: 0x00000001
    Locator: 10.11.11.11, priority: 9, weight: 50
             Uptime: 02:19:51, state: up, local
  Registering more-specific dynamic-EIDs
  Registering routes: disabled
  Map-Server(s): none configured, use global Map-Server
  Site-based multicast Map-Notify group: none configured
  Number of roaming dynamic-EIDs discovered: 1
  Last dynamic-EID discovered: 172.16.54.1, 00:00:58 ago
  Roaming dynamic-EIDs:
    172.16.54.200, (null), uptime: 00:17:50, last activity: 00:00:25
      Discovered by: EID-Notify
      EID-Notify Locators:
        10.3.3.3
        10.4.4.4


MS_MR#sh lisp site 172.16.54.200
LISP Site Registration Information
Site name: 1
Allowed configured locators: any
Requested EID-prefix:
  EID-prefix: 172.16.54.200/32
    First registered:     02:02:24
    Routing table tag:    0
    Origin:               Dynamic, more specific of 172.16.54.0/24
    Merge active:         No
    Proxy reply:          No
    TTL:                  00:03:00
    State:                complete
    Registration errors:
      Authentication failures:   0
      Allowed locators mismatch: 0
    ETR 10.11.17.1, last registered 00:00:32, no proxy-reply, map-notify
                    TTL 00:03:00, no merge, hash-function sha1, nonce 0x00000000-0x00000000
                    state complete, no security-capability
                    xTR-ID N/A
                    site-ID N/A
      Locator      Local  State      Pri/Wgt  Scope
      10.11.11.11  yes    up           9/50   IPv4 none

步骤9.两个xTR都可以更新映射缓存条目。

在VM迁移之前，对于站点3,VM IP的RLOC是West xTR(10.10.10.10)。 将VM迁移到东DC后，一旦West xTR收到来自站点3的流量，它就会将SMR消息发送到站点3路由器，以更新East xTR(10.11.11.11)的新RLOC地址，如下所示：

Site-3#sh ip lisp map-cache
LISP IPv4 Mapping Cache for EID-table default (IID 0), 2 entries

0.0.0.0/0, uptime: 02:03:23, expires: never, via static send map-request
  Negative cache entry, action: send-map-request
172.16.54.200/32, uptime: 02:00:22, expires: 23:57:56, via map-reply, complete
  Locator      Uptime    State      Pri/Wgt
  10.11.11.11  00:02:03  up           9/50


N7K-FA8-East_xTR(config)# show ip lisp map-cache
LISP IP Mapping Cache for VRF "default" (iid 0), 1 entries
* = Locator data counters are cumulative across all EID-prefixes

172.16.20.0/24, uptime: 00:25:24, expires: 23:34:35, via map-reply, auth
  Locator      Uptime    State       Priority/  Data      Control       MTU
                                     Weight     in/out    in/out
  10.20.20.20  00:25:24  up          10/50      0/0*      0/0          1500

验证

使用本部分可确认配置能否正常运行。

验证在步骤5中介绍。在“操作顺序”部分。

故障排除

本部分提供了可用于对配置进行故障排除的信息。

这些调试可用于排除受控环境中的LISP故障。

debug ip lisp mapping control

debug lisp mapping register

debug lisp smr

debug lisp ha

debug lisp loc-reach-algorithm receive-probe

debug lisp loc-reach-algorithm send-probe

debug ip mroute map_notify_addr 32 detail

debug ip lisp mapping data