HP 6120XG ProCurve Series 6120 Blade Switches Management and Configuration Gui - Page 338

Port Traffic Controls Jumbo Frames Jumbo Frames Feature display VLAN jumbo status configure jumbo VLANs Default Menu CLI Web n/a - 12-23 - Disabled - 12-25 - The Maximum Transmission Unit (MTU) is the maximum size IP frame the switch can receive for Layer 2 frames inbound on a port. The switch drops any inbound frames larger than the MTU allowed on the port. On ports operating at 10 Mbps or 100 Mbps, the MTU is fixed at 1522 bytes. However, ports operating at 1 Gbs or 10 Gbps speeds accept forward frames of up to 9220 bytes (including four bytes for a VLAN tag) when configured for jumbo traffic. You can enable inbound jumbo frames on a per-VLAN basis. That is, on a VLAN configured for jumbo traffic, all ports belonging to that VLAN and operating at 1 Gbs or 10 Gbps allow inbound jumbo frames of up to 9220 bytes. (Regardless of the mode configured on a given jumbo-enabled port, if the port is operating at only 10 Mbps or 100 Mbps, only frames that do not exceed 1522 bytes are allowed inbound on that port.) Terminology Jumbo Frame: An IP frame exceeding 1522 bytes in size. The maximum Jumbo frame size is 9220 bytes. (This size includes 4 bytes for the VLAN tag.) Jumbo VLAN: A VLAN configured to allow inbound jumbo traffic. All ports belonging to a jumbo and operating at 1 Gbps or higher can receive jumbo frames from external devices. If the switch is in a meshed domain, then all meshed ports (operating at 1 Gbps or higher) on the switch will accept jumbo traffic from other devices in the mesh. MTU (Maximum Transmission Unit): This is the maximum-size IP frame the switch can receive for Layer 2 frames inbound on a port. The switch allows jumbo frames of up to 9220 bytes. (This size includes 4 bytes for the VLAN tag.) Standard MTU: An IP frame of 1522 bytes in size. (This size includes 4 bytes for the VLAN tag.) 12-20