HP 6120G/XG ProCurve Series 6120 Blade Switches Management and Configuration G - Page 291

Port Traffic Controls Jumbo Frames If there are security concerns with grouping the ports as shown for VLAN 300, you can either use source-port filtering to block unwanted traffic paths or create separate jumbo VLANs, one for ports 6 and 7, and another for ports 12 and 13. ■ Outbound Jumbo Traffic. Any port operating at 1 Gbps or higher can transmit outbound jumbo frames through any VLAN, regardless of the jumbo configuration. The VLAN is not required to be jumbo-enabled, and the port is not required to belong to any other, jumbo enabled VLANs. This can occur in situations where a non-jumbo VLAN includes some ports that do not belong to another, jumbo-enabled VLAN and some ports that do belong to another, jumbo-enabled VLAN. In this case, ports capable of receiving jumbo frames can forward them to the ports in the VLAN that do not have jumbo capability. 1 2 34 56 Jumbo-Enabled VLAN VLAN 10 Non-Jumbo VLAN VLAN 20 Port 3 belongs to both VLAN 10 and VLAN 20. Jumbo frames received inbound on port 3 can be forwarded out the Non-Jumbo ports 4, 5, and 6. Figure 12-4. Forwarding Jumbo Frames Through Non-Jumbo Ports Jumbo frames can also be forwarded out non-jumbo ports when the jumbo frames received inbound on a jumbo-enabled VLAN are routed to another, non-jumbo VLAN for outbound transmission on ports that have no memberships in other, jumbo-capable VLANs. Where either of the above scenarios is a possibility, the downstream device must be configured to accept the jumbo traffic. Otherwise, this traffic will be dropped by the downstream device. 12-10