RAD Data comm IPmux-11 operation manual Framed, Cas

Installation and Operation Manual Chapter 1 Introduction

Configuring the TDM bytes per frame (TDM bytes/frame) parameter has impact on the Ethernet throughput (bandwidth or traffic traveling through the Ethernet). This parameter controls the number of TDM bytes encapsulated in one frame.

The TDM bytes/frame parameter can be configured to N ⋅ 48 bytes where N is an integer between 1 and 30.

To calculate Ethernet throughput as a function of TDM bytes/frame:

Ethernet load (bps) = [(frame overhead (bytes) + TDM bytes/frame) ⋅ 8] ⋅ frames/second

Frame overhead = Ethernet overhead + IP overhead = 46 bytes

Note The frame overhead does not include:

•Preamble field: 7 bytes

•SFD field: 1 byte

•Interframe gap: 12 bytes

•VLAN field (when used): 4 bytes.

Frame/second =

Unframed: 5447/n for a full E1 4107/n for a full T1

Framed: 8000 ⋅ k/(46.875 x n) Where k = number of assigned timeslots

Where n = TDM bytes/frame 48

The maximum Ethernet throughput mode is calculated by:

Unframed

(VLAN + frame overhead + payload) * 1444444244444443 frame size

⎧	data	⎫
⎪	64748
	8000 * TS ⎪
⎨	47 * n	⎬ * 8 bits
⎪		⎪
⎪		⎪
⎩		⎭

Framed

	⎧	data	pointer	CAS		⎫
	⎪		64748	64748		⎪
	⎪	64748	8000 * TS	⎡ TS ⎤		⎪
		8000 * TS +	(47 * 8) - 1	+ 500 * ⎢	⎥
	⎪			⎢ 2	⎥	⎪
(VLAN + frame overhead + payload) * ⎨						⎬	* 8 bits
			47 * n
1444444244444443	⎪					⎪
frame size	⎪					⎪
	⎪					⎪
	⎩					⎭

IPmux-11 Ver. 2.00 Functional Description 1-13