DescriptionWhat is the MTU in "show interfaces Dot11radio ap_id interface_id"
ScopeKB
ARTICLE TYPE: Troubleshooting
RELATED
SOFTWARE VERSIONS: 4.x,
5.x
KEYWORDS:
MTU, Dot11Radio
SolutionThe
802.11 MTU (Maximum Transmission Unit) for data frames is 2304 bytes
(frame payload size before encryption). The value of 2304 bytes as the
maximum length of this field was chosen to allow an application to send
2048-byte pieces of information, which can then be encapsulated by as
many as 256 bytes of upper layer protocol headers and
trailers.The IEEE 802.11 header is fairly complex; it is
between 24 and 30 bytes (standard Ethernet header is 14
bytes).
Based on the
encryption method use, the final payload size varies:
1 WEP
adds a header of 8 bytes for a total of 2312 bytes.
2 WPA
(TKIP) adds a header of 20 bytes for a total of 2324 bytes.
3
WPA2 (AES) adds a header of 16 bytes, for a total of 2320
bytes
The output of "show
interfaces Dot11Radio ap_id interface_id" show MTU as 2346 that is
correct and it talks about dot11
MTU.
