What is a Jumbo Frame and what Enterasys products support them

FAQ_User — Sat, 16 Nov 2013 00:44:00 GMT

Article ID: 1184

Goals
Jumbo Frame Support

Symptoms
Jumbo Frames
Oversize frames

Cause
A Jumbo Frame is an ethernet frame containing a data field larger than the maximum 1500 bytes specified by the IEEE 802.3 Ethernet standard. A 1500-byte data field yields a 1518-byte Ethernet_II frame size, after adding the DA/SA/Type/FCS fields.

Typically a jumbo frame will be between 9k-64k bytes in size. Jumbo frames are a result of the need to be able to increase data transfer rates across larger data paths. With the increased usage of Gigabit and 10 Gigabit Ethernet, the 1500 MTU limit is not the most useful in terms of processing of packets and effective use of the bandwidth. With Jumbo frames there is less fragmentation requiring the use of processing resources.

9K Jumbo frames are typically used because Ethernet uses a 32 bit CRC. Frames larger than that make the use of the CRC ineffective. A 9K frame size easily handles an 8K block size used with NFS. A 64K Frame size is the maximum limit for IPV4 datagrams. IPV6 will theoretically support a maximum framesize of 4GB.

Solution
Devices supporting Jumbo frames:

X-pedition, T-Series gigabit linecards only, 64K frames
Matrix E1, f/w 3.00.14+, gigabit ports only; 6K frames
1G694-13, f/w 1.02.04+, h/w rev 0H+), gigabit ports only; 6K frames
Matrix DFE (4th Generation); gigabit ports only; 10K (10,239 byte) frames (12390)
Matrix X-Series; at least 9K
SecureStack; 9K (9,216 byte) frames (11750)
G-Series; 9K (9,216 byte) frames (11750)

topic What is a Jumbo Frame and what Enterasys products support them in FAQs

What is a Jumbo Frame and what Enterasys products support them