Wired Core Configuration

The most critical point of connectivity in a campus LAN, the network core is designed for simplicity and reliability. Relative to the rest of the network, the core provides high-speed, high-bandwidth, Layer 3 connectivity between the various aggregation points across the campus.

The network core also provides services aggregation functions when needed. Deciding where to locate network services, such as gateway devices, depends on the number of access aggregation switches and where user applications are hosted. Refer to the ESP Campus Design Validated Solution Guide for further discussion.

Configure the Core Switch Group

The following procedures describe the creation of a core switch configuration in CLI format. The switch configuration can be created offline in a text editor and copied into MultiEdit, or it can be typed directly in MultiEdit in a UI group of Central. Switches in the group receive the configuration when synchronized to Central.

The figure below shows the standalone core switches in the Aruba ESP Campus.

Wired Core

Enable MultiEdit for the Group

The base configuration of the switch was previously described in the Switch Group Configuration section of this guide. The following procedure completes the switch configuration using the Aruba Central MultiEdit tool, a CLI-based configuration editor built into Central.

Step 1 Go to Central and login using administrator credentials.

Step 2 On the Aruba Central Account Home page, launch the Network Operations app.

Step 3 In the filter dropdown, select a core switch Group name. On the left menu, select Devices.

Step 4 In the upper right of the Switches page, select Config.

Step 5 In the upper left of the Switches page, move the slider right to enable MultiEdit.

Step 6 Select the devices for editing. In the lower right window, click EDIT CONFIG.

Configure Routers and Loopback Interfaces

In the following procedure, Open Shortest Path First (OSPF) routing is configured and neighbor relationships are established between aggregation and core switches by configuring point-to-point IP links using /30 subnets. Then, Protocol Independent Multicast-Sparse Mode (PIM-SM) routing is enabled on the same links to ensure that multicast streams coming from the core can flow to the access VLANs. Loopback interfaces are created for the routers.

The figure below can be used as a reference point for the implemented configuration.

OSPF Topology

Note: After pasting a configuration in the MultiEdit window, right-click any device-specific values. A Modify Parameters window appears on the right to allow input of individual device values when entering configuration for multiple devices.

Step 1 Configure the global OSPF routing instance with area 0 and enable passive-interface default to avoid unwanted OSPF adjacencies. Use a pre-allocated loopback IP address as the router-id. When a chassis has redundant management modules, enable graceful-restart.

router ospf 1
  area 0 
  passive-interface default
  router-id 10.0.0.1
  redistribute bgp
  graceful-restart restart-interval 30

Step 2 Configure multicast routing globally.

router pim
  enable

Step 3 Configure OSPF on the loopback interface. Create the loopback 0 interface and configure the IP address using the router ID from the earlier step. Enable OSPF with area 0.

interface loopback 0
  ip address 10.0.0.1/32
  ip pim-sparse enable
  ip ospf 1 area 0

Step 4 Create a new loopback interface with the Anycast IP address. Enable PIM-SM and OSPF.

interface loopback 1
  ip address 10.0.0.100/32
  ip pim-sparse enable
  ip ospf 1 area 0

Configure Multicast Routing

In the following procedure, the core is configured as a rendezvous point (RP) candidate using the loopback 1 anycast IP address and a bootstrap router (BSR) candidate using the loopback 0 IP address. Then MSDP is configured to share multicast group source addresses.

Step 1 Configure the RP candidate source IP interface using loopback 1, and the BSR candidate source IP interface using loopback 0. Set the RP-candidate group prefix and the BSR-candidate priority.

Example: Core 1 Switch

router pim
    enable
    rp-candidate source-ip-interface loopback1 group-prefix 224.0.0.0/4
    bsr-candidate source-ip-interface loopback0
    bsr-candidate priority 1

Example: Core 2 Switch

router pim
    enable
    rp-candidate source-ip-interface loopback1 group-prefix 224.0.0.0/4
    bsr-candidate source-ip-interface loopback0

Note: The RP candidate group prefix should be adjusted based on the IP design of the local network. The 224.0.0.0/4 prefix assigns all multicast groups to the RP.

Step 2 Configure MSDP globally. The MSDP peer is the IP address of the loopback 0 interface on the adjacent core switch. The local loopback 0 interface is the connect-source.

Example: Core 1 Switch

router msdp 
    enable 
    ip msdp peer 10.0.0.1
        connect-source loopback0
        enable
        mesh-group RSVCP

Example: Core 2 Switch

router msdp 
    enable 
    ip msdp peer 10.0.0.1
        connect-source loopback0
        enable
        mesh-group RSVCP

Note: The mesh-group must be specified to exchange multicast group source address (SA) information, even when only two switches are participating in MSDP. An MSDP peer relationship will form without the mesh-group specificiation, but no SA information will be exchanged.

At the bottom right of the MultiEdit window, click Save.

Verify MSDP

Step 3 In a Remote Console window, type the command show ip msdp summary, then press ENTER. The output shown below indicates that MSDP source address (SA) information is sent from Core 1 to Core 2.

Note: Execute the show ip msdp summary on both core routers when a multicast source is active to verify SA information is exchanged. The SA Count value on at least one core router should be above zero.

Configure Switch Interfaces

Next, each physical interface connected to an aggregation switch is configured for OSPF and PIM-SM routing.

Step 1 Configure OSPF and PIM-SM on the physical interfaces. Configure a large IP MTU, turn off OSPF passive mode, set the OSPF network to point-to-point, and enable OSPF using the router process and area.

interface 1/1/1 
  description CORE_TO_AGG1
  no shutdown
  ip mtu 9198
  ip address 172.18.103.2/30
  no ip ospf passive
  ip ospf network point-to-point
  ip ospf 1 area 0
  ip pim-sparse enable

Step 2 Repeat the previous step for each interface between the core and aggregation switches.

Example: Core 1 Switch

Example: Core 2 Switch

Configure Data Center Connectivity

Many campuses have a locally attached data center. With this arrangement, routing must be established between the two networks so that clients in the campus can access applications in the data center. In the OWL, Corp. campus, BGP is used to peer with the data center border to learn the routes needed by clients.

Step 1 Create VLANs and SVIs for peering between the campus core and data center border. Each VLAN SVI becomes the BGP neighbor and participates in OSPF for the campus.

vlan 2011
    name DC1_FB1_PROD_LF1-1
vlan 2013
    name DC1_FB1_PROD_LF2-1

...

interface vlan 2011
    description DC1_FB1_PROD_LF1-1
    ip mtu 9198
    ip address 172.18.100.63/31
    ip ospf 1 area 0.0.0.0
    ip ospf passive
interface vlan 2013
    description DC1_FB1_PROD_LF2-1
    ip mtu 9198
    ip address 172.18.100.67/31
    ip ospf 1 area 0.0.0.0
    ip ospf passive

Step 2 Configure the physical interfaces connected to the data center border to trunk the VLANs created above.

interface 1/3/5
    description RSVDC-FB1-LF1-1
    no shutdown
    mtu 9198
    no routing
    vlan trunk native 1
    vlan trunk allowed 2011
interface 1/3/6
    description RSVDC-FB1-LF1-2
    no shutdown
    mtu 9198
    no routing
    vlan trunk native 1
    vlan trunk allowed 2013

Step 3 Configure the BGP router to peer with the routers running on the data center border switches.

router bgp 65000
    bgp router-id 10.0.0.1
    neighbor 172.18.100.62 remote-as 65001
    neighbor 172.18.100.62 fall-over bfd
    neighbor 172.18.100.66 remote-as 65001
    neighbor 172.18.100.66 fall-over bfd
    address-family ipv4 unicast
        neighbor 172.18.100.62 activate
        neighbor 172.18.100.62 default-originate
        neighbor 172.18.100.66 activate
        neighbor 172.18.100.66 default-originate
    exit-address-family

Step 4 At the bottom right of the MultiEdit window, click Save.

Verify BGP Operation

Central provides a remote console capability that allows for CLI access on any managed switch. Use this to run CLI show commands at validation steps throughout this guide.

Step 1 On the left menu, select Tools.

Step 2 On the Console tab, assign the following settings, then select Create New Session.

• Device Type: Switch

• Switch: Device name

• Username: admin

• Password: password

Step 3 In the Remote Console window, type the command show bgp ipv4 unicast summary, then press ENTER. The output shown below indicates healthy BGP sessions to data center border switches.

Step 4 In the Remote Console window, type the command show ip route bgp, then press ENTER. The output shown below shows the routes learned from the data center border switches.

Configure Internet Connectivity

Step 1 Configure an interface on each switch to provide Internet connectivity. In the OWL, Corp. campus, internet service is provided through a firewall running OSPF. The core switches use OSPF to peer with the firewall and learn the default route.

interface 1/3/11
    description RSVCP-INET
    no shutdown
    mtu 9198
    routing
    ip mtu 9000
    ip address 192.168.8.9/31
    ip ospf 1 area 0.0.0.0
    no ip ospf passive
    ip ospf network point-to-point

Note: Devices in the group automatically synchronize the new configuration. Synchronization status is updated on the Configuration Status page. Process step execution can be observed by clicking Audit Trail on the left menu. Verification of OSPF routing is performed during aggregation switch deployment.