Static Scoping of Multicast Streams via 'set mac multicast'

[FAQ_User]

Article ID: 5708

Products
Matrix E1
Matrix N-Series DFE
Matrix X-Series
SecureStack C3
SecureStack C2
SecureStack B3
SecureStack B2
SecureStack A2
S-Series
G-Series
D-Series
I-Series
X-Pedition

Related to
Microsoft
Load balancing
NLB
Stonebeat

Commands
'set mac multicast'

Goals
Static scoping of Multicast streams
Block unwanted multicast

Cause
Some products do or will support the setting of static multicast MAC addresses ('set mac multicast'), so that these addresses may be scoped to only the configured ports. IGMP may further prune these flows if they fall under its purview.

One of the key purposes of this command is to support the multicast version of various NIC-based proprietary "Load Balancing" technologies, including NLB and Stonebeat. These multicast streams are not typically constrained by IGMP, because they combine a Multicast ("01-00-5E-xx-xx-xx") MAC address with a Unicast IP address.

Solution
Currently supporting the 'set mac multicast' command:

• Matrix E1, firmware 3.07.02 and higher (granularity to VLAN)
• Matrix N-Series DFE, firmware 5.21.24 and higher (9287 - granularity to Ports)
• Matrix X-Series, firmware 1.5.1 and higher (granularity to Ports)
• SecureStack C3, firmware 1.00.80 and higher (granularity to Ports)
• SecureStack C2, firmware 5.00.59 and higher (granularity to Ports)
• SecureStack B3, firmware 1.00.74 and higher (granularity to Ports)
• SecureStack B2, firmware 4.00.60 and higher (granularity to Ports)
• SecureStack A2, firmware upcoming (granularity to Ports)
• S-Series, all firmware (9287 - granularity to Ports)
• G-Series, all firmware (granularity to Ports)
• D-Series, all firmware (granularity to Ports)
• I-Series, all firmware (granularity to Ports)
• X-Pedition (granularity to VLAN - 'arp add <cluster_IP> mac-addr <cluster_MAC> vlan <cluster_VLAN_name>')

Note that the specific implementation/format of this command differs, on the above products - though the net result is the same: scoping these multicasts to the desired ports.

Providing this functionality through a routed interface

The described 'set mac multicast' command functions on switched Layer 2, accommodating requests to the server cluster using a multicast MAC address (propagating to all servers) and replies to individual clients using standard unicast (propagating to the requesting client). If such traffic is also expected to operate through a routed Layer 3 interface (for instance, intercepting a unicast request for server data, from a client on a different VLAN), this requires the additional step of statically setting an ARP entry binding the servers' virtual IP address with the L2 multicast MAC address.

Setting a Static ARP entry using a Multicast MAC address is supported on the following subset of equipment:

Matrix N-Series

• At Layer 2: 'set mac multicast...'
• At Layer 3: 'Router(config)#arp...'
• For more: Please refer to the Matrix N Configuration Guide, Chapter 12, "Network Address and Route Management Configuration".

Matrix X-Series

• At Layer 2: 'set mac multicast...'
• At Layer 3: 'Router(config)#arp...',

'Router(config)#no ip host-mobility...'

• For more: Please refer to the Matrix X Configuration Guide, Chapter 26, "Configuring Server Cluster Support".

S-Series

• At Layer 2: 'set mac multicast...'
• At Layer 3: '(router-config)->arp...'
• For more: Please refer to the S-Series Configuration Guide, Chapter 19, "IP Routing Configuration".

See also: 12596 and 14129.

Contact Enterasys Networks Technical Services for an update, as necessary.