© 2019 Cisco and/or its affiliates. All rights reserved. Page 9 of 43
Fabric wireless LAN controller
The fabric WLC integrates with the fabric control plane. Both fabric WLCs and non-fabric WLCs provide AP image and
configuration management, client session management, and mobility services. Fabric WLCs provide additional services for
fabric integration, by registering MAC addresses of wireless clients into the host tracking database of the fabric control plane
during wireless client join events, and by supplying fabric edge RLOC location updates during client roam events.
A key difference with non-fabric WLC behavior is that fabric WLCs are not active participants in the data plane traffic-
forwarding role for the SSIDs that are fabric enabled—fabric mode APs directly forward traffic to the fabric edges for those
SSIDs.
Typically, the fabric WLC devices connect to a shared services distribution or data center outside the fabric and fabric border,
which means that their management IP address exists in the global routing table. For the wireless APs to establish a CAPWAP
tunnel for WLC management, the APs must be in a VN that has access to the external device. In the SD-Access solution, Cisco
DNA Center configures wireless APs to reside within the VRF named INFRA_VRF, which maps to the global routing table,
avoiding the need for route leaking or fusion router (multi-VRF router selectively sharing routing information) services to
establish connectivity. Each fabric site has to have a WLC unique to that site. It is recommended to place the WLC in the local
site itself because of latency requirements for SD-Access. Latency is covered in a section below in more detail.
Small- to medium-scale deployments of Cisco SD-Access can use the Cisco Catalyst 9800 Embedded Wireless Controller. The
controller is available for the Catalyst 9300 Switch as a software package update to provide wired and wireless (fabric only)
infrastructure with consistent policy, segmentation, security and seamless mobility, while maintaining the ease of operation of
the Cisco Unified Wireless Network. The wireless control plane remains unchanged, using CAPWAP tunnels initiating on the
APs and terminating on the Cisco Catalyst 9800 Embedded Wireless Controller. The data plane uses VXLAN encapsulation for
the overlay traffic between the APs and the fabric edge.
The Catalyst 9800 Embedded Wireless Controller for Catalyst 9300 Series software package enables wireless functionality only
for Cisco SD-Access deployments with two supported topologies:
●
Cisco Catalyst 9300 Series switches functioning as colocated border and control plane.
●
Cisco Catalyst 9300 Series switches functioning as a fabric in a box.
The embedded controller only supports fabric mode access points.
Fabric mode access points
The fabric mode APs are Cisco WiFi6 (802.11ax) and 802.11ac Wave 2 and Wave 1 APs associated with the fabric WLC that have
been configured with one or more fabric-enabled SSIDs. Fabric mode APs continue to support the same wireless media services
that traditional APs support; apply AVC, quality of service (QoS), and other wireless policies; and establish the CAPWAP control
plane to the fabric WLC. Fabric APs join as local-mode APs and must be directly connected to the fabric edge node switch to
enable fabric registration events, including RLOC assignment via the fabric WLC. The fabric edge nodes use CDP to recognize
APs as special wired hosts, applying special port configurations and assigning the APs to a unique overlay network within a
common EID space across a fabric. The assignment allows management simplification by using a single subnet to cover the AP
infrastructure at a fabric site.
When wireless clients connect to a fabric mode AP and authenticate into the fabric-enabled wireless LAN, the WLC updates the
fabric mode AP with the client Layer 2 VNI and an SGT supplied by ISE. Then the WLC registers the wireless client Layer 2 EID
into the control plane, acting as a proxy for the egress fabric edge node switch. After the initial connectivity is established, the
AP uses the Layer 2 VNI information to VXLAN-encapsulate wireless client communication on the Ethernet connection to the
directly-connected fabric edge switch. The fabric edge switch maps the client traffic into the appropriate VLAN interface
associated with the VNI for forwarding across the fabric and registers the wireless client IP addresses with the control plane
database.
更多资源请访问鸿鹄论坛:http://bbs.hh010.com/