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]>
Date:  Thursday, August 29, 2013 7:37 AM
To:  "[email protected]" <[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
> 
>  
> _______________________________________________
> emane-users mailing list
> [email protected]http://pf.itd.nrl.navy.mil/mailman/listinfo/ema
> ne-users



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