Cisco无线控制器C9800-CL：为什么推荐RP上连到交换机而不是WLC直连？

Cisco无线控制器C9800：为什么推荐RP上连到交换机而不是WLC直连？

网关检测
Default Gateway Check
Default Gateway check is done by periodically sending Internet Control Message Protocol (ICMP) ping to the gateway. Both  the active and the standby controllers use the RMI IP as the source IP. These messages are sent at 1 second interval. If there are 8 consecutive failures in reaching the gateway, the controller will declare the gateway as non-reachable.
After 4 ICMP Echo requests fail to get ICMP Echo responses, ARP requests are attempted. If there is no response for 8 seconds (4 ICMP Echo Requests followed by 4 ARP Requests), the gateway is assumed to be non-reachable. Currently, this feature supports IPv4 only.
默认网关检查
默认网关检查是通过定期向网关发送ICMP (Internet Control Message Protocol) ping来完成的。主控制器和备用控制器都使用RMI IP作为源IP。这些消息每隔1秒发送一次。如果连续8次无法到达网关，控制器将声明网关不可达。
当4次ICMP Echo请求没有得到ICMP Echo响应后，尝试ARP请求。如果在8秒内（4次ICMP Echo request和4次ARP request）没有响应，则认为网关不可达。目前该特性只支持IPv4。

The Catalyst 9800 Wireless controller has two recovery states to prevent an active-active scenario.
Recovery mode logically means a state where the controller does not have all “resources” available to provide the service.
Currently, RP, RMI and Gateway are the resources. Ports will be in admin down in recovery mode, so no traffic goes
through.
Catalyst 9800无线控制器有两种恢复状态，以防止双活场景。
恢复模式在逻辑上是指控制器没有所有可用的“资源”来提供服务的状态。
目前，RP， RMI和Gateway是资源。端口将处于admin down恢复模式，因此没有流量
通过。
■ Standby-Recovery: If Gateway goes down, standby goes to standby-recovery mode. Standby means, its state is
up to date with the active. But since it does not have the other resource (Gateway) it goes to Standby-Recovery.
The standby shall not be in a position to take over the active functionality when it is in standby-recovery mode.
Standby-Recovery will go back to Standby without a reload, once it detects that the Gateway reachability is
restored.
■standby-recovery：当Gateway发生故障时，standby进入standby-recovery模式。待机表示，其状态为
最新的活跃。但是由于它没有其他资源（网关），它进入备用恢复。
当待机处于待机恢复模式时，待机不能接管主动功能。
一旦检测到网关的可达性，Standby- recovery将返回到Standby状态而不需要重新加载
恢复。
■ Active-Recovery is when the RP goes down. Active-Recovery does not have its internal state in sync with the
Active. Active-Recovery will reload when the RP link comes up so that it can come up as Standby with bulk sync.
Switchover history will show switchover reason as Gateway down in the event of a switchover triggered as a result of the
gateway going down.
主动恢复是指RP下降。Active-Recovery的内部状态不与
活跃。Active-Recovery将在RP链路启动时重新加载，以便它可以作为批量同步的备用链路启动。
切换历史记录将显示切换原因为Gateway down
大门关闭。


Default Gateway Check WebUI Configuration
The default gateway check option can be configured under Administration > Device > Redundancy > Management Gateway Failover

Default Gateway Check CLI Configuration
The following CLIs need to be configured for the gateway check functionality to be enabled and to specify the default gateway IP used by this feature
需要配置以下cli以启用网关检查功能，并指定此特性使用的默认网关IP

WLC-9800(config)#management gateway-failover enable
WLC-9800#ip default-gateway <IP>
To verify if gateway check is enabled, use the CLI show redundancy state
WLC-9800#show redundancy states
 my state = 13 -ACTIVE
 peer state = 8 -STANDBY HOT
 Mode = Duplex
 Unit = Primary
Unit ID = 2
Redundancy Mode (Operational) = sso
Redundancy Mode (Configured) = sso
Redundancy State = sso
…
Gateway Monitoring = Enabled

With 17.2, usage of “ip default-gateway ” shall be removed . Gateway IP will be picked up from the static IP routes configured. The HA infrastructure will choose the static route IP that matches the RMI network. If there are multiple static routes configured, the route configured for the broadest network scope shall be selected. It is possible to configure multiple gateways for the same network scope. If there are multiple gateways for the same network, broadest mask and least gateway IP is chosen. The gateway IP shall be reevaluated, if necessary, when config update to static routes happens.
在17.2中，“ip default-gateway”的用法将被删除。网关IP将从配置的静态IP路由中拾取。HA基础结构将选择与RMI网络匹配的静态路由IP。如果配置了多条静态路由，则选择网络范围最广的路由。可以为同一个网络范围配置多个网关。如果同一网络中有多个网关，则选择最宽掩码和最小网关IP。当配置更新为静态路由时，需要重新评估网关IP。

Note:
•Physical port down scenario takes 8 seconds to be detected as it is detected via GW check mechanism
•Physical port status is synced from the active to standby controller in release 17.1. This has been fixed in release 17.2 and the active and standby controllers maintain their own port status.
注意:
•物理端口down场景需要8秒才能被检测到，因为是通过GW检测机制检测到的
•17.1版本中，物理端口状态从主备控制器同步。这个问题在17.2版中得到了修复，活动控制器和备用控制器保持各自的端口状态。

面向云的思科 Catalyst 9800-CL 无线控制器
https://www.cisco.com/c/zh_cn/support/wireless/catalyst-9800-cl-wireless-controller-cloud/model.html
Cisco Catalyst 9800-CL Wireless Controller for Cloud
https://www.cisco.com/c/en/us/support/wireless/catalyst-9800-cl-wireless-controller-cloud/model.html

Cisco Catalyst 9800 系列无线控制器
https://www.cisco.com/site/cn/zh/products/networking/wireless/wireless-lan-controllers/catalyst-9800-series/index.html


 
16.x 只能支持RP
https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/213915-configure-catalyst-9800-wireless-control.html
17.X 支持RP 和RMI 2种
https://www.cisco.com/c/dam/en/us/td/docs/wireless/controller/9800/17-2/deployment-guide/c9800-ha-sso-deployment-guide-rel-17-2.pdf