标题: [GSM:3gpp] 44.006中"Address field format"相关疑问[查看完整版帖子][打印本页]
时间: 2014-2-6 17:33
作者: 风情123 标题: [GSM:3gpp] 44.006中"Address field format"相关疑问
请教下各位好心人:
最近在看44.006,遇到以下疑问:
"
6.2 Address field format
The field consists of:
the address field extension bit EA;
the command/response bit C/R;
the SAPI;
and the Link Protocol Discriminator LPD.
The format of the address field for control channels is shown in figure 4.
The address field extension bit, EA, enables extension of the field to span more than one octet. The value "0" is used to indicate an extension, the value "1" shall be used for the final address field octet.
The Link Protocol Discriminator (LPD) corresponding to the use in this Technical Specification shall take the value "0 0", all other values are reserved.
NOTE: LPD = "0 1" corresponds to the data link protocol used for SMSCB (see 3GPP TS 44.012).
Bit 8 7 6 5 4 3 2 1
Spare LPD SAPI C/R EA
=1
Figure 4: Address field format
"
问题如下:
问题1:
上述若EA为1可以理解,也即到此结束,即Address 的Size为1字节(即8bits)
但是若EA=0时,那么怎样判断Address到哪里结束呢?
问题2:
这个Address 理论上应该是用于识别目的地,但是从上面未见哪里可以识别目的地的阿?(也即未见哪里可以唯一标识目的地的)
再顺便请教下:44.006中:
"8.4.1.4 Contention resolution establishment procedure"中
If an SABM command with an information field is received when the "establishment in process" flag has been set,the data link layer entity in the BS shall compare the store information field with the information field received in the SABM command. If they are not identical, the SABM command shall be ignored without any notification. If they are identical, the data link layer entity shall respond, at the earliest possible opportunity, with a UA response with:
主要比较迷惑的是发送SABM command中带有信息域的,说是进行与"the data link layer entity in the BS "进行比较,不是很懂"the data link layer entity in the BS "里面都有什么的??按理说未发SABM command时对端应该没有"SABM command"中信息域的任何信息,怎么可以比较呢??