请教一个原理性的问题......

fans008

<p>传输设备在处理开销中有穿通和终结两种模式,关于这两种模式我想大家也都一定清楚,一个是只读取不修改,一个是读取且重置,我不展开了</p><p>那么请问:是不是一定要有相应的功能块(比如HPT,LPT)才能有这种设置的功能? 而没有功能块的地方就根本不会提取或者检测开销?</p><p>之所以有此一问,是因为我看到某写书上有如下逻辑图</p><p><span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'mso-font-kerning:1.0pt;mso-bidi-font-family:'mso-hansi-font-family:'mso-bidi-font-size:12.0pt;mso-ansi-language:en-us;mso-fareast-language:zh-cn;mso-bidi-language:ar-sa;;">SDH信号------SPI接口--RST--MST--MSP--MSA-----HPC</span></p><p><span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'mso-font-kerning:1.0pt;mso-bidi-font-family:'mso-hansi-font-family:'mso-bidi-font-size:12.0pt;mso-ansi-language:en-us;mso-fareast-language:zh-cn;mso-bidi-language:ar-sa;;">DH140M信号--PPI接口--LPA--HPT---------------HPC</span></p><p><span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'mso-font-kerning:1.0pt;mso-bidi-font-family:'mso-hansi-font-family:'mso-bidi-font-size:12.0pt;mso-ansi-language:en-us;mso-fareast-language:zh-cn;mso-bidi-language:ar-sa;;">DH2M信号----PPI接口-LPA-LPT--LPC--HPA--HPT--HPC</span></p><p><span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'mso-font-kerning:1.0pt;mso-bidi-font-family:'mso-hansi-font-family:'mso-bidi-font-size:12.0pt;mso-ansi-language:en-us;mso-fareast-language:zh-cn;mso-bidi-language:ar-sa;;">按照这个图,可以看到,SDH单板上没有HPT,所以我就想问这个HPT到底存在于什么地方?SDH板?交叉板OR PDH板?</span></p><p><span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'mso-font-kerning:1.0pt;mso-bidi-font-family:'mso-hansi-font-family:'mso-bidi-font-size:12.0pt;mso-ansi-language:en-us;mso-fareast-language:zh-cn;mso-bidi-language:ar-sa;;"></span></p>