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来自「用C++编写的GPRS协议栈源代码」· HTML 代码 · 共 63 行
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<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"><!--Converted with LaTeX2HTML 96.1 (Feb 5, 1996) by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds --><HTML><HEAD><TITLE>Radio Link Control (RLC)</TITLE><META NAME="description" CONTENT="Radio Link Control (RLC)"><META NAME="keywords" CONTENT="gprs"><META NAME="resource-type" CONTENT="document"><META NAME="distribution" CONTENT="global"><LINK REL=STYLESHEET HREF="gprs.css"></HEAD><BODY LANG="EN"> <A NAME="tex2html464" HREF="node35.html"><IMG WIDTH=37 HEIGHT=24 ALIGN=BOTTOM ALT="next" SRC="http://cbl.leeds.ac.uk/nikos/figs/next_motif.gif"></A> <A NAME="tex2html462" HREF="node1.html"><IMG WIDTH=26 HEIGHT=24 ALIGN=BOTTOM ALT="up" SRC="http://cbl.leeds.ac.uk/nikos/figs/up_motif.gif"></A> <A NAME="tex2html456" HREF="node33.html"><IMG WIDTH=63 HEIGHT=24 ALIGN=BOTTOM ALT="previous" SRC="http://cbl.leeds.ac.uk/nikos/figs/previous_motif.gif"></A> <BR><B> Next:</B> <A NAME="tex2html465" HREF="node35.html">RLC class in C++</A><B>Up:</B> <A NAME="tex2html463" HREF="node1.html">The General Packet Radio </A><B> Previous:</B> <A NAME="tex2html457" HREF="node33.html">Resources have to be </A><BR> <P><H1><A NAME="SECTION00140000000000000000">Radio Link Control (RLC)</A></H1><P>A new layer called Radio Link Control is added to the wireless node,between the LL and IFQ<A NAME="tex2html2" HREF="footnode.html#269"><IMG ALIGN=BOTTOM ALT="gif" SRC="http://cbl.leeds.ac.uk/nikos/figs/foot_motif.gif"></A>. This required changes in <I> ns</I>/tcl/lib/ns-mobilenode.tcl<P> The main features included are fragmentation and assembly, along with RLCretransmissions. The retransmit mechanism is a simplified form of SelectiveRetransmits. The fragmentation-reassembly and acknowledgements may beconfigured ON or OFF by the user and the RLC fragment size can be set. A newheader, the RLC header is introduced. Though this was written as a part of GPRS stack implementation, it can beused independently with any other stack with minor modifications.<P>In case an RLC fragment is dropped by the MAC, in acknowledged mode, aduplicate acknowledgment for the last correctly received RLC fragment issentback to the sender, which then retransmits the expected RLC fragment.In unacknowledged mode, if an RLC fragment is missing, the RLC does notpass any of the fragments to the LL. The LL in this case, would re-send theLL fragment (if in acknowledged mode) or will let the higher layers (ieTCP) handle it.In acked mode, currently only one MS can be supported.<P>In GPRS. the actual size of an RLC packet's payload depends on the codingscheme used. We take the average GPRS RLC payload size to be 200 bytes. InGPRS these 200 bytes are transmitted over four slots in consecutive TDMAframes,amounting to 50 bytes per slot. To model this, the RLC fragments areconfigured to be of 50 bytes and thus 50 bytes are transmitted in each TDMAslot.<P><BR> <HR><UL> <LI> <A NAME="tex2html466" HREF="node35.html#SECTION00141000000000000000">RLC class in C++</A><LI> <A NAME="tex2html467" HREF="node36.html#SECTION00142000000000000000">Parameters</A><LI> <A NAME="tex2html468" HREF="node37.html#SECTION00143000000000000000">Modifications for use outside GPRS</A><LI> <A NAME="tex2html469" HREF="node38.html#SECTION00144000000000000000">To bypass the RLC</A></UL><BR> <HR><P><ADDRESS><I>Richa Jain (96D07007) <BR>Tue Jul 24 22:29:53 IST 2001</I></ADDRESS></BODY></HTML>⌨️ 快捷键说明
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