一、说明
- 与上一篇"1 实验1:基于静态Ingress Replication实现Cisco VxLAN & 集中式网关"相同，基于Multicast实现VxLAN也是流量驱动式的MAC地址泛洪学习和VTEP邻居建立，没有控制层面；
- 与基于Static Ingress Replication实现VxLAN不同，基于Multicast实现VxLAN无需手动为每个VNI配置peer；
- 当有流量触发即数据驱动时，VTEP之间的隧道才会自动建立；
- 与利用Static Ingress Replication实现BUM(广播、未知单播、组播)流量转发不同，基于Multicast实现BUM流量的转发可有效节省VTEP上行链路的带宽(具体参考组播网络特性)。
二、基于Multicast实现的VxLAN实验
2.1 实验环境
| 工具 | 版本 | 备注 |
|---|---|---|
| EVE-NG | 2.0.3-105 | 模拟器 |
| Cisco Nexus 9000v | 7.0.3.I7.8 | 支持VxLAN的交换机，拓扑中的N9K1、N9K-2、N9K-3和N9K-4 |
| Wireshark | 3.2.2 | 抓包软件 |
2.2 实验拓扑
image.png
- N9K1、N9K-2、N9K-3和N9K-4运行OSPF协议；
- N9K1、N9K-2、N9K-3和N9K-4运行PIM Sparse Mode，其中PIM RP为1.1.1.1；
- 实现PC1、PC2和PC3能互通。
2.3 实验配置
2.3.1 配置Underlay三层网络
- 设备的互联接口、Loopback接口都通告进OSPF Area 0。
N9K-1配置：
feature ospf
router ospf n9k-1
router-id 1.1.1.1
interface Ethernet1/1
no switchport
mtu 9216
ip address 10.1.1.1/30
ip ospf network point-to-point
ip router ospf n9k-1 area 0.0.0.0
no shutdown
interface Ethernet1/2
no switchport
mtu 9216
ip address 10.1.1.5/30
ip ospf network point-to-point
ip router ospf n9k-1 area 0.0.0.0
no shutdown
interface Ethernet1/3
no switchport
mtu 9216
ip address 10.1.1.9/30
ip ospf network point-to-point
ip router ospf n9k-1 area 0.0.0.0
no shutdown
interface loopback0
ip address 1.1.1.1/32
ip router ospf n9k-1 area 0.0.0.0
N9K-2配置：
vlan 10
feature ospf
router ospf n9k-2
router-id 2.2.2.2
interface Ethernet1/1
no switchport
mtu 9216
ip address 10.1.1.2/30
ip ospf network point-to-point
ip router ospf n9k-2 area 0.0.0.0
no shutdown
interface loopback0
ip address 2.2.2.2/32
ip router ospf n9k-2 area 0.0.0.0
interface Ethernet1/2
switchport access vlan 10
spanning-tree port type edge
N9K-3配置：
vlan 10
feature ospf
router ospf n9k-3
router-id 3.3.3.3
interface Ethernet1/1
no switchport
mtu 9216
ip address 10.1.1.6/30
ip ospf network point-to-point
ip router ospf n9k-3 area 0.0.0.0
no shutdown
interface loopback0
ip address 3.3.3.3/32
ip router ospf n9k-3 area 0.0.0.0
interface Ethernet1/2
switchport access vlan 10
spanning-tree port type edge
N9K-4配置：
vlan 10
feature ospf
router ospf n9k-4
router-id 4.4.4.4
interface Ethernet1/1
no switchport
mtu 9216
ip address 10.1.1.10/30
ip ospf network point-to-point
ip router ospf n9k-4 area 0.0.0.0
no shutdown
interface loopback0
ip address 4.4.4.4/32
ip router ospf n9k-4 area 0.0.0.0
interface Ethernet1/2
switchport access vlan 10
spanning-tree port type edge
配置验证：
查看N9K-1 OSPF路由表：
N9K-1# show ip route ospf
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%' in via output denotes VRF
2.2.2.2/32, ubest/mbest: 1/0
*via 10.1.1.2, Eth1/1, [110/41], 2d10h, ospf-n9k-1, intra
3.3.3.3/32, ubest/mbest: 1/0
*via 10.1.1.6, Eth1/2, [110/41], 2d10h, ospf-n9k-1, intra
4.4.4.4/32, ubest/mbest: 1/0
*via 10.1.1.10, Eth1/3, [110/41], 2d10h, ospf-n9k-1, intra
查看N9K-2 OSPF路由表：
N9K-2# show ip route ospf
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%' in via output denotes VRF
1.1.1.1/32, ubest/mbest: 1/0
*via 10.1.1.1, Eth1/1, [110/41], 2d10h, ospf-n9k-2, intra
3.3.3.3/32, ubest/mbest: 1/0
*via 10.1.1.1, Eth1/1, [110/81], 2d10h, ospf-n9k-2, intra
4.4.4.4/32, ubest/mbest: 1/0
*via 10.1.1.1, Eth1/1, [110/81], 2d10h, ospf-n9k-2, intra
10.1.1.4/30, ubest/mbest: 1/0
*via 10.1.1.1, Eth1/1, [110/80], 2d10h, ospf-n9k-2, intra
10.1.1.8/30, ubest/mbest: 1/0
*via 10.1.1.1, Eth1/1, [110/80], 2d10h, ospf-n9k-2, intra
查看N9K-3 OSPF路由表：
N9K-3# show ip route ospf
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%' in via output denotes VRF
1.1.1.1/32, ubest/mbest: 1/0
*via 10.1.1.5, Eth1/1, [110/41], 2d10h, ospf-n9k-3, intra
2.2.2.2/32, ubest/mbest: 1/0
*via 10.1.1.5, Eth1/1, [110/81], 2d10h, ospf-n9k-3, intra
4.4.4.4/32, ubest/mbest: 1/0
*via 10.1.1.5, Eth1/1, [110/81], 2d10h, ospf-n9k-3, intra
10.1.1.0/30, ubest/mbest: 1/0
*via 10.1.1.5, Eth1/1, [110/80], 2d10h, ospf-n9k-3, intra
10.1.1.8/30, ubest/mbest: 1/0
*via 10.1.1.5, Eth1/1, [110/80], 2d10h, ospf-n9k-3, intra
查看N9K-4 OSPF路由表：
N9K-4# show ip route ospf
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%' in via output denotes VRF
1.1.1.1/32, ubest/mbest: 1/0
*via 10.1.1.9, Eth1/1, [110/41], 2d10h, ospf-n9k-4, intra
2.2.2.2/32, ubest/mbest: 1/0
*via 10.1.1.9, Eth1/1, [110/81], 2d10h, ospf-n9k-4, intra
3.3.3.3/32, ubest/mbest: 1/0
*via 10.1.1.9, Eth1/1, [110/81], 2d10h, ospf-n9k-4, intra
10.1.1.0/30, ubest/mbest: 1/0
*via 10.1.1.9, Eth1/1, [110/80], 2d10h, ospf-n9k-4, intra
10.1.1.4/30, ubest/mbest: 1/0
*via 10.1.1.9, Eth1/1, [110/80], 2d10h, ospf-n9k-4, intra
2.3.2 配置Underlay Multicast网络
- 设备的互联接口、Loopback接口都启用Multicast。
N9K-1配置：
feature pim
ip pim rp-address 1.1.1.1 group-list 239.0.0.0/24
interface loopback0
ip pim sparse-mode
interface Ethernet1/1
ip pim sparse-mode
interface Ethernet1/2
ip pim sparse-mode
interface Ethernet1/3
ip pim sparse-mode
N9K-2配置：
feature pim
ip pim rp-address 1.1.1.1 group-list 239.0.0.0/24
interface loopback0
ip pim sparse-mode
interface Ethernet1/1
ip pim sparse-mode
N9K-3配置：
feature pim
ip pim rp-address 1.1.1.1 group-list 239.0.0.0/24
interface loopback0
ip pim sparse-mode
interface Ethernet1/1
ip pim sparse-mode
N9K-4配置：
feature pim
ip pim rp-address 1.1.1.1 group-list 239.0.0.0/24
interface loopback0
ip pim sparse-mode
interface Ethernet1/1
ip pim sparse-mode
配置验证：
- 首先应使用命令"show ip pim neighbor"检查组播邻居；
- 当有BUM报文触发组播流量后才会有完整组播路由表，以下组播路由表为参考。
查看N9K-1 Multicast路由表：
N9K-1# show ip mroute
IP Multicast Routing Table for VRF "default"
(*, 232.0.0.0/8), uptime: 06:25:14, pim ip
Incoming interface: Null, RPF nbr: 0.0.0.0
Outgoing interface list: (count: 0)
(*, 239.0.0.1/32), uptime: 06:11:39, pim ip
Incoming interface: loopback0, RPF nbr: 1.1.1.1
Outgoing interface list: (count: 3)
Ethernet1/1, uptime: 00:00:49, pim
Ethernet1/2, uptime: 00:00:55, pim
Ethernet1/3, uptime: 00:01:02, pim
(2.2.2.2/32, 239.0.0.1/32), uptime: 06:11:18, pim mrib ip
Incoming interface: Ethernet1/1, RPF nbr: 10.1.1.2, internal
Outgoing interface list: (count: 3)
Ethernet1/1, uptime: 00:00:49, pim, (RPF)
Ethernet1/2, uptime: 00:00:55, pim
Ethernet1/3, uptime: 00:01:02, pim
(3.3.3.3/32, 239.0.0.1/32), uptime: 06:11:06, pim mrib ip
Incoming interface: Ethernet1/2, RPF nbr: 10.1.1.6, internal
Outgoing interface list: (count: 3)
Ethernet1/1, uptime: 00:00:49, pim
Ethernet1/2, uptime: 00:00:55, pim, (RPF)
Ethernet1/3, uptime: 00:01:02, pim
(4.4.4.4/32, 239.0.0.1/32), uptime: 06:10:58, pim mrib ip
Incoming interface: Ethernet1/3, RPF nbr: 10.1.1.10, internal
Outgoing interface list: (count: 3)
Ethernet1/3, uptime: 00:00:39, pim, (RPF)
Ethernet1/1, uptime: 00:00:49, pim
Ethernet1/2, uptime: 00:00:55, pim
查看N9K-2 Multicast路由表：
N9K-2# show ip mroute
IP Multicast Routing Table for VRF "default"
(*, 232.0.0.0/8), uptime: 06:26:48, pim ip
Incoming interface: Null, RPF nbr: 0.0.0.0
Outgoing interface list: (count: 0)
(*, 239.0.0.1/32), uptime: 06:13:07, ip pim nve
Incoming interface: Ethernet1/1, RPF nbr: 10.1.1.1
Outgoing interface list: (count: 1)
nve1, uptime: 00:02:16, nve
(2.2.2.2/32, 239.0.0.1/32), uptime: 06:13:07, mrib ip pim nve
Incoming interface: loopback0, RPF nbr: 2.2.2.2
Outgoing interface list: (count: 1)
Ethernet1/1, uptime: 00:02:29, pim
查看N9K-3 Multicast路由表：
N9K-3# show ip mroute
IP Multicast Routing Table for VRF "default"
(*, 232.0.0.0/8), uptime: 06:26:50, pim ip
Incoming interface: Null, RPF nbr: 0.0.0.0
Outgoing interface list: (count: 0)
(*, 239.0.0.1/32), uptime: 06:13:15, ip pim nve
Incoming interface: Ethernet1/1, RPF nbr: 10.1.1.5
Outgoing interface list: (count: 1)
nve1, uptime: 00:02:36, nve
(3.3.3.3/32, 239.0.0.1/32), uptime: 06:13:15, mrib ip pim nve
Incoming interface: loopback0, RPF nbr: 3.3.3.3
Outgoing interface list: (count: 1)
Ethernet1/1, uptime: 00:02:43, pim
查看N9K-4 Multicast路由表：
N9K-4# show ip mroute
IP Multicast Routing Table for VRF "default"
(*, 232.0.0.0/8), uptime: 06:27:20, pim ip
Incoming interface: Null, RPF nbr: 0.0.0.0
Outgoing interface list: (count: 0)
(*, 239.0.0.1/32), uptime: 06:13:47, ip pim nve
Incoming interface: Ethernet1/1, RPF nbr: 10.1.1.9
Outgoing interface list: (count: 1)
nve1, uptime: 00:03:21, nve
(4.4.4.4/32, 239.0.0.1/32), uptime: 06:13:47, mrib ip pim nve
Incoming interface: loopback0, RPF nbr: 4.4.4.4
Outgoing interface list: (count: 1)
Ethernet1/1, uptime: 00:03:14, pim
2.3.3 配置Overlay网络
- 同一VNI都加入到相同组播组，本实验中组播组为239.0.0.1。
N9K-2配置：
vlan 10
vn-segment 10010
interface nve1
no shutdown
source-interface loopback0
member vni 10010
mcast-group 239.0.0.1
N9K-3配置：
vlan 10
vn-segment 10010
interface nve1
no shutdown
source-interface loopback0
member vni 10010
mcast-group 239.0.0.1
N9K-4配置：
vlan 10
vn-segment 10010
interface nve1
no shutdown
source-interface loopback0
member vni 10010
mcast-group 239.0.0.1
配置验证：
查看N9K-2 NVE的VNI和Peers状态：
N9K-2# show nve vni
Codes: CP - Control Plane DP - Data Plane
UC - Unconfigured SA - Suppress ARP
SU - Suppress Unknown Unicast
Xconn - Crossconnect
MS-IR - Multisite Ingress Replication
Interface VNI Multicast-group State Mode Type [BD/VRF] Flags
--------- -------- ----------------- ----- ---- ------------------ -----
nve1 10010 239.0.0.1 Up DP L2 [10]
N9K-2# show nve peers
N9K-2#
查看N9K-3 NVE的VNI和Peers状态：
N9K-3# show nve vni
Codes: CP - Control Plane DP - Data Plane
UC - Unconfigured SA - Suppress ARP
SU - Suppress Unknown Unicast
Xconn - Crossconnect
MS-IR - Multisite Ingress Replication
Interface VNI Multicast-group State Mode Type [BD/VRF] Flags
--------- -------- ----------------- ----- ---- ------------------ -----
nve1 10010 239.0.0.1 Up DP L2 [10]
N9K-3# show nve peers
N9K-3#
查看N9K-4 NVE的VNI和Peers状态：
N9K-4# show nve vni
Codes: CP - Control Plane DP - Data Plane
UC - Unconfigured SA - Suppress ARP
SU - Suppress Unknown Unicast
Xconn - Crossconnect
MS-IR - Multisite Ingress Replication
Interface VNI Multicast-group State Mode Type [BD/VRF] Flags
--------- -------- ----------------- ----- ---- ------------------ -----
nve1 10010 239.0.0.1 Up DP L2 [10]
N9K-4# show nve peers
N9K-4#
从以上结果可看出，目前VTEP之间并没有VxLAN隧道建立。
2.4 实验验证
2.4.1 PC IP配置
PC1配置：
VPCS> show ip all
NAME IP/MASK GATEWAY MAC DNS
VPCS1 172.16.1.1/24 0.0.0.0 00:50:79:66:68:05
PC2配置：
VPCS> show ip all
NAME IP/MASK GATEWAY MAC DNS
VPCS1 172.16.1.2/24 0.0.0.0 00:50:79:66:68:06
PC3配置：
VPCS> show ip all
NAME IP/MASK GATEWAY MAC DNS
VPCS1 172.16.1.3/24 0.0.0.0 00:50:79:66:68:07
2.4.2 触发流量
PC1触发流量：
VPCS> ping 172.16.1.2
host (172.16.1.2) not reachable
VPCS> ping 172.16.1.2
84 bytes from 172.16.1.2 icmp_seq=1 ttl=64 time=44.744 ms
84 bytes from 172.16.1.2 icmp_seq=2 ttl=64 time=49.071 ms
84 bytes from 172.16.1.2 icmp_seq=3 ttl=64 time=34.025 ms
84 bytes from 172.16.1.2 icmp_seq=4 ttl=64 time=43.254 ms
84 bytes from 172.16.1.2 icmp_seq=5 ttl=64 time=32.700 ms
VPCS> ping 172.16.1.3
84 bytes from 172.16.1.3 icmp_seq=1 ttl=64 time=45.851 ms
84 bytes from 172.16.1.3 icmp_seq=2 ttl=64 time=47.016 ms
84 bytes from 172.16.1.3 icmp_seq=3 ttl=64 time=44.488 ms
84 bytes from 172.16.1.3 icmp_seq=4 ttl=64 time=43.073 ms
84 bytes from 172.16.1.3 icmp_seq=5 ttl=64 time=65.783 ms
PC2触发流量：
VPCS> ping 172.16.1.3
host (172.16.1.3) not reachable
VPCS> ping 172.16.1.3
84 bytes from 172.16.1.3 icmp_seq=1 ttl=64 time=34.228 ms
84 bytes from 172.16.1.3 icmp_seq=2 ttl=64 time=27.838 ms
84 bytes from 172.16.1.3 icmp_seq=3 ttl=64 time=62.914 ms
84 bytes from 172.16.1.3 icmp_seq=4 ttl=64 time=47.581 ms
84 bytes from 172.16.1.3 icmp_seq=5 ttl=64 time=25.724 ms
2.4.3 检查VxLAN隧道
N9K-2 VxLAN隧道：
N9K-2# show nve peers
Interface Peer-IP State LearnType Uptime Router-Mac
--------- --------------- ----- --------- -------- -----------------
nve1 3.3.3.3 Up DP 00:02:30 n/a
nve1 4.4.4.4 Up DP 00:02:20 n/a
N9K-3 VxLAN隧道：
N9K-3# show nve peers
Interface Peer-IP State LearnType Uptime Router-Mac
--------- --------------- ----- --------- -------- -----------------
nve1 2.2.2.2 Up DP 00:02:42 n/a
nve1 4.4.4.4 Up DP 00:02:14 n/a
N9K-4 VxLAN隧道：
N9K-4# show nve peers
Interface Peer-IP State LearnType Uptime Router-Mac
--------- --------------- ----- --------- -------- -----------------
nve1 2.2.2.2 Up DP 00:02:55 n/a
nve1 3.3.3.3 Up DP 00:02:28 n/a
从以上结果可看出，经过流量触发后，VTEP间的VxLAN隧道才会自动建立。
2.4.4 检查VxLAN MAC地址表
N9K-2 MAC地址表：
N9K-2# show system internal l2fwder mac
Legend:
* - primary entry, G - Gateway MAC, (R) - Routed MAC, O - Overlay MAC
age - seconds since last seen,+ - primary entry using vPC Peer-Link,
(T) - True, (F) - False, C - ControlPlane MAC
VLAN MAC Address Type age Secure NTFY Ports
---------+-----------------+--------+---------+------+----+------------------
* 10 0050.7966.6805 dynamic 00:00:58 F F Eth1/2
* 10 0050.7966.6806 dynamic 00:00:58 F F (0x47000001) nve-peer1
3.3.3.3
* 10 0050.7966.6807 dynamic 00:00:56 F F (0x47000002) nve-peer2
4.4.4.4
N9K-3 MAC地址表：
N9K-3# show system internal l2fwder mac
Legend:
* - primary entry, G - Gateway MAC, (R) - Routed MAC, O - Overlay MAC
age - seconds since last seen,+ - primary entry using vPC Peer-Link,
(T) - True, (F) - False, C - ControlPlane MAC
VLAN MAC Address Type age Secure NTFY Ports
---------+-----------------+--------+---------+------+----+------------------
* 10 0050.7966.6805 dynamic 00:01:25 F F (0x47000001) nve-peer1
2.2.2.2
* 10 0050.7966.6806 dynamic 00:01:25 F F Eth1/2
* 10 0050.7966.6807 dynamic 00:01:16 F F (0x47000002) nve-peer2
4.4.4.4
N9K-4 MAC地址表：
N9K-4# show system internal l2fwder mac
Legend:
* - primary entry, G - Gateway MAC, (R) - Routed MAC, O - Overlay MAC
age - seconds since last seen,+ - primary entry using vPC Peer-Link,
(T) - True, (F) - False, C - ControlPlane MAC
VLAN MAC Address Type age Secure NTFY Ports
---------+-----------------+--------+---------+------+----+------------------
* 10 0050.7966.6805 dynamic 00:01:28 F F (0x47000001) nve-peer1
2.2.2.2
* 10 0050.7966.6806 dynamic 00:01:19 F F (0x47000002) nve-peer2
3.3.3.3
* 10 0050.7966.6807 dynamic 00:01:27 F F Eth1/2
有关MAC地址详细学习流程可参考"实验1:基于静态Ingress Replication实现Cisco VxLAN "。
2.5 报文分析
2.5.1 BUM报文分析
- 对N9K-2的E1/1口抓包；
- 清空PC1和PC2的ARP表，从PC1 ping PC2。
清空PC1的ARP表：
VPCS> arp
00:50:79:66:68:06 172.16.1.2 expires in 118 seconds
VPCS> clear arp
VPCS> arp
arp table is empty
VPCS>
清空PC2的ARP表：
VPCS> arp
00:50:79:66:68:05 172.16.1.1 expires in 93 seconds
VPCS> clear arp
VPCS> arp
arp table is empty
VPCS>
BUM报文抓包：
以ARP请求报文为例
image.png
组播转发说明：
- 在N9K-1即PIM RP上，对于来自2.2.2.2并去往239.0.0.1的数据包，N9K-1会将该数据包转发至E1/2和E1/3接口；
- 同理，从任何源去往239.0.0.1数据包，数据包都会被转发到所有其它加入组播组239.0.0.1的VTEP；
- 与基于Static Ingress Replication实现VxLAN不同，基于Multicast实现VxLAN中的BUM流量由Underlay的组播网络传输；
- 最佳实践：使用Anycast RP以实现RP的负载均衡和冗余(本实验未使用Anycast RP)，下图为Cisco Nexus交换机Anycast RP配置示例：
image.png
2.5.2 单播报文分析
- 对N9K-2的E1/1口抓包；
单播报文抓包：
以ARP回复报文为例
image.png
三、集中式网关
- 目标：N9K-2作为集中式网关，更改PC3的IP为172.16.2.1，实现PC3能与PC1、PC2互访；
- 不再演示外部路由设备作为网关，外部路由设备作为网关可参考实验1；
- 不再演示抓包。
变更N9K-2的配置：
feature interface-vlan
vlan 20
vn-segment 10020
interface Vlan10
no shutdown
ip address 172.16.1.254/24
interface Vlan20
no shutdown
ip address 172.16.2.254/24
interface nve1
member vni 10020
mcast-group 239.0.0.2
变更N9K-4的配置：
vlan 20
vn-segment 10020
interface nve1
no member vni 10010
member vni 10020
mcast-group 239.0.0.2
interface Ethernet1/2
switchport access vlan 20
变更PC1的配置-配上网关：
VPCS> ip 172.16.1.1 255.255.255.0 172.16.1.254
Checking for duplicate address...
PC1 : 172.16.1.1 255.255.255.0 gateway 172.16.1.254
变更PC2的配置-配上网关：
VPCS> ip 172.16.1.2 255.255.255.0 172.16.1.254
Checking for duplicate address...
PC1 : 172.16.1.2 255.255.255.0 gateway 172.16.1.254
变更PC3的配置-修改IP：
VPCS> ip 172.16.2.1 255.255.255.0 172.16.2.254
Checking for duplicate address...
PC1 : 172.16.2.1 255.255.255.0 gateway 172.16.2.254
测试：
从PC3 ping PC1
VPCS> ping 172.16.1.1
84 bytes from 172.16.1.1 icmp_seq=1 ttl=63 time=44.051 ms
84 bytes from 172.16.1.1 icmp_seq=2 ttl=63 time=52.670 ms
84 bytes from 172.16.1.1 icmp_seq=3 ttl=63 time=94.949 ms
84 bytes from 172.16.1.1 icmp_seq=4 ttl=63 time=48.976 ms
84 bytes from 172.16.1.1 icmp_seq=5 ttl=63 time=50.364 ms
从PC3 ping PC2
VPCS> ping 172.16.1.2
84 bytes from 172.16.1.2 icmp_seq=1 ttl=63 time=66.403 ms
84 bytes from 172.16.1.2 icmp_seq=2 ttl=63 time=68.189 ms
84 bytes from 172.16.1.2 icmp_seq=3 ttl=63 time=67.867 ms
84 bytes from 172.16.1.2 icmp_seq=4 ttl=63 time=86.699 ms
84 bytes from 172.16.1.2 icmp_seq=5 ttl=63 time=75.751 ms
从PC2 ping PC1
VPCS> ping 172.16.1.1
84 bytes from 172.16.1.1 icmp_seq=1 ttl=64 time=41.983 ms
84 bytes from 172.16.1.1 icmp_seq=2 ttl=64 time=46.274 ms
84 bytes from 172.16.1.1 icmp_seq=3 ttl=64 time=40.682 ms
84 bytes from 172.16.1.1 icmp_seq=4 ttl=64 time=51.736 ms
84 bytes from 172.16.1.1 icmp_seq=5 ttl=64 time=44.748 ms
如果集中式网关配置完毕并检查无误后，如果不通，可尝试保存并重启N9K！
四、总结
基于Static Ingress Replications实现VxLAN优势：
- VTEP的受控部署；
- 简化故障排除流程。
基于Static Ingress Replications实现VxLAN劣势：
- 配置和维护负担增加；
- 必须在每个VTEP上手工配置每个peer，容易出现配置错误。
基于Multicast实现VxLAN优势：
- 减少配置和维护负担；
- 具有灵活的可扩展性；
- 有效减少VTEP上行链路带宽占用，因为VTEP仅需将BUM流量的一份副本发给RP，RP再转发给其它VTEP；
- 配置简单，流量触发后自动建立VxLAN隧道。
基于Multicast实现VxLAN劣势：
- 每个VNI使用一个组播组；
- 使用组播协议会增加排错复杂性。