Re: [emane-users] EMANE RF Pipe Header Size

Kaushik B. Patel Thu, 29 Aug 2013 12:39:35 -0700

Bow-Nan, I incorrectly added the 28 bytes for MGEN. So the total is only 48 bytes.

kb


Kaushik B. Patel
Adjacent Link LLC
CEO, Director of Engineering
908.655.5079
[email protected]

On 08/29/2013 01:03 PM, Cheng, Bow-Nan - 0665 - MITLL wrote:

Thanks KB,
I think I'm still a bit confused where the 28 bytes comes from. In MGEN, the 28 byte header is not an extra header added, but subtracted from the payload. So when you do a TCPdump on the interface for a 100 Byte MGEN UDP packet, you'll see:
IPv4: 20 bytes
UDP: 8 bytes
Data: 100 bytes (28 bytes MGEN information + 72 bytes padded information)
Assuming that the Ethernet header is 14 bytes and the common MAC header is 6 bytes, then we're still missing 28 bytes somewhere that's being added.
Any thoughts would be greatly appreciated. I can also run tests if you want me to print something specific. Thanks!
-Bow-Nan
From: "Kaushik B. Patel" <[email protected] <mailto:[email protected]>>
Date: Thursday, August 29, 2013 7:37 AM
To: "[email protected] <mailto:[email protected]>" <[email protected] <mailto:[email protected]>>
Subject: Re: [emane-users] EMANE RF Pipe Header Size
Bow-Nan, with EMANE v0.8.1, the common MAC header is 6 bytes. The RF-Pipe does not have its own MAC header.
So if you are sending a 100 byte UDP packet using MGEN, you will see a total of 176 bytes from MAC to PHY via your statistic.
The breakdown of the 176 bytes is as follows:

Payload:   100
Ethernet: 14
IP:           20
UDP:       8
MGEN:    28
RF-Pipe MAC:  6

Total:  176

kb
On 08/28/2013 02:40 PM, Cheng, Bow-Nan - 0665 - MITLL wrote:
Hello,
We've added a statistic to track bytes sent downstream from MAC to PHY using the pkt.length() function. One thing we're noticing is that for RF Pipe, an extra 48 bytes is being added is being added for the "MAC" header. I was wondering what this would correspond to and/or where I can find out what contributes to the RF Pipe MAC header? Ethernet is about 14 Bytes and I believe 802.11 is somewhere around 28.. But I'm not sure where 48 bytes is coming from. Any thoughts would be greatly appreciated. Thanks!
-Bow-Nan


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Re: [emane-users] EMANE RF Pipe Header Size

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