sis-協(xié)議分析(中文版)

1、DOCSIS － 協(xié)議分析,議 程,介紹 DOCSIS； DOCSIS PHY； DOCSIS MAC DOCSIS CM與CMTS的交互過程； 介紹 DOCSIS 1.1； DOCSIS 1.1 關(guān)鍵概念； DOCSIS QoS 特性集； 新 MAC 管理消息； 分段數(shù)據(jù)包（Fragmentation）； DOCSIS 1.1 安全； DOCSIS 1.1 上行調(diào)度算法； Concatenation； 數(shù)據(jù)有效

2、負載幀頭壓縮； DOCSIS 2.0 Protocol Analysis。,DOCSIS Protocol 演變,,,,,1997,DOCSIS 1.0,,1999,,,DOCSIS 1.1,,,,DOCSIS 2.0,2001,1995,,,MCNS,DOCSIS 標準,,,,,,,,,,,,,,,,,,x 4,,,Splitters 2 or 3 Way,Dual Window SM Fiber 1310 / 1550 nm,

3、Dual Window FO Transceivers,Multitaps 8 Port,Amplifiers 1GHz 2-Way,,,,Cable Modem,Customer Premises Equipment,CMTS,DOCSIS Network Servers Provisioning DHCP TFTP ToD,TOD,TFTP,DHCP,PROV,交換機 / 路由器,,,,,,,

4、,,,,,,,,,,,,,,,,,,,,1 GHz Coaxial Cable,,,,,,Upstream,Downstream,,OSSI(Operations Support System Interface),CMTS-NSI(CMTS Network Side Interface Specifications ),RFI(Radio Frequency Interface Specifications ),BPI-/BPI

5、+(Security Interface ),CMCI(Cable Modem Customer Side Interface Specifications ),,DOCSIS 1.0 功能,開放協(xié)議性 非私有的。支持CM即插即用被設(shè)計為盡力可達早期版本標準不指定CM最小速率；由用戶在1.0 CMs和CMTSs間設(shè)定最小速率；支持盡力可達和CIR（保證最低的傳輸速率）的網(wǎng)絡(luò)服務(wù)； CIR(Committed Infor

6、mation rate): 除了突發(fā)，正常時提供CM的最小速率。不支持 CBR（承諾速率）服務(wù)。靈活性:DOCSIS 1.0增加 MAC和 PHY參數(shù)，靈活控制CM，以確保網(wǎng)絡(luò)的穩(wěn)健。安全與管理BPI(Baseline Privacy)和BPI＋管理CM。兼容SNMP。遠程軟件更新。,,,CMTS架構(gòu)HFC的參考模型,,,,Tx,Rx,,,,,,,,,,,,,,,,CATV分配網(wǎng),,,,,,,,,,,,,,,,,Vide

7、o 1,Video 2,Data,下行混頻器,上行分支器,Data,,調(diào)制,,解調(diào),,,,,邏輯橋接、路由,CMTS,前 端,,IP骨干網(wǎng),,交換機路由器光傳輸,,CM(透明橋),,,,CPE,DOCSIS與CATV頻譜,下行頻率 88-860 MHz,上行 5- 42/65 MHz,8,802.3 Ethernet, ATM MAC LAYER,DOCSIS 協(xié)議簇,802.3 Ethernet, ATM

8、 MAC LAYER,Fiber Optic, Coax, UTP Copper PHYSICAL LAYER,Cable MAC SUBLAYER,LLC Security SUBLAYER,Downstream Transmission Convergence SUBLAYER,Cable PMD SUBLAYER,Upstr

9、eam Cable PMD,,,,,,,,,,,,,,,,,,,Internet Protocol [IP] NETWORK LAYER,FTP DHCP TFTP SMTP SNMP Telnet [ports] APPLICATIONS LAYER,Internet Protocol [IP] NETWORK LAYER,FTP DHCP TFTP SMTP SNMP Telnet [ports]

10、 APPLICATIONS LAYER,IP RoutingRIP, OSPF,MAC Transparent Bridging,Cable MAC SUBLAYER,LLC Security SUBLAYER,Downstream Transmission Convergence SUBLAYER,Cable PMD SUBLAYER,Upstream Cable PMD,Internet P

11、rotocol [IP] NETWORK LAYER,FTP DHCP TFTP SMTP SNMP Telnet [ports] APPLICATIONS LAYER,Fiber Optic, Coax, UTP Copper PHYSICAL LAYER,Internet Protocol [IP] NETWORK LAYER,FTP DHCP T

12、FTP SMTP SNMP Telnet [ports] APPLICATIONS LAYER,x 4,,,,,,,MAC Transparent Bridging,,CMTS,CM,HFC Network,,,,,,,,,,,,,,,Hybrid Fiber Optic Coaxial

13、 [HFC] Network PHYSICAL LAYER,,,,,9,DOCSIS與OSI,北美－DOCSIS 1.x 下行 [Physical Media

14、 Dependent Sublayer],下行：91-857 MHz，+/- 30khz6 MHz channel widths連續(xù)調(diào)制兩種調(diào)制類型：64QAM、256QAM兩種符號速率 5.0 MSymbols per sec 5.3 MSymbols per sec一端發(fā)送多端接收CM偵聽下行信號,6 bits per symbol,8 bits per symbol,Data Rate,Bandwidth,歐標DO

15、CSIS 是基于 DOCSIS 1.0/ 1.1 規(guī)范制定的歐標物理子層和MAC； DVB( Digital Video Broadcasting )在下行8MHz通道QAM調(diào)制； 64或256 QAM 可達到 6.952Msps 符號速率； 5 - 65 MHz 上行頻率范圍,歐洲－DOCSIS 1.x 下行[Physical Media Dependent Sublayer],北美－DOCSIS 1.x 上行

16、[Physical Media Dependent Sublayer],上行 5-30/42MHz在 UCD中定義符號速率時分多址 （TDMA）：把時間分割成周期性的幀(Frame)每一個幀再分割成若干個時隙向CMTS發(fā)送信號,一點對多點的接收方式CM數(shù)據(jù)在上行調(diào)制發(fā)送,MPEG Headerpointer_field DOCSIS Payload (4 bytes)

17、(1 byte) (183 or 184 bytes),北美－DOCSIS 1.x PHY,下行傳輸匯聚子層（PHY)MPEG II 幀長為：183/184 bytes MPEG 數(shù)據(jù)幀頭 PID為：0x1FFE,MPEG Header Continuation of MAC Frame # 1 (4 bytes)

18、(184 bytes),MPEG Headerpointer_field Tail of MAC # 1 (4 bytes)(1 byte) M bytes M bytes,Start of MAC # 2,一個MPEG幀頭可裝載多個DOCSIS MAC 幀,MPEG Headerpointer field Start of MAC

19、frame # 1 (4 bytes) (1 byte) (up to 183 bytes),,,,,,,,,DOCSIS－MAC層,CMTS對CM作帶寬分配控制；在上行，時隙和時隔又由微時隙(mini—slot)組成；帶寬分配的最小單位：微時隙支持CoS（Class of Service）；安全：BPI；服務(wù)標識 －

20、 SIDs 14 bits0x0000 未初始化的 CM SID；0x3FFF 信令，對所有 CMs；組播 SIDs用于請求或數(shù)據(jù)包；組播 MAC 01:E0:2F:00:00:01。,,,DOCSIS－MAC幀類型,,FC_Type,,FC_PARM,,EHDRON,EHDR LENConc Frame countRequests,LengthorSID,00: Ethernet11: Mac Header,,,

21、00000 Ethernet00000 Timing00001 Mac Man00010 Req11100 Concat,,,Extended MAC headers,0 to 240 bytes,,,DOCSIS timing 參數(shù),Map Lead time：前置時間；The sync message：同步消息；Minislot size：微時隙大??；分配開始時間和時間偏移量；CM到CMTS的上行時延。,DOCSIS

22、 MAC 管理消息,SYNC Timing Synchronization：同步消息；UCD：上行通道描述 ；MAP Upstream Bandwidth Allocation：上行帶寬分配；RNG-REQ：Ranging 請求；RNG-RSP：Ranging 響應(yīng)；REG-REQ：注冊請求；REG-RSP：注冊響應(yīng)；UCC-REQ：上行通道改變請求；UCC-RSP：上行通道改變響應(yīng)；BPKM-REQ：密鑰管理請求 [

23、DOCSIS8]BPKM-RSP：密鑰管理響應(yīng) [DOCSIS8],CM and CMTS 交互過程,CM掃描并與下行同步；CMTS獲得上行參數(shù)；CMTS Ranging、自動調(diào)節(jié)物理參數(shù)與CM適配；建立IP連接；建立ToD(time of day)；向CM傳輸操作參數(shù)；注冊；BPI(Baseline Privacy initialization)：可選。,獲取下行通道和時間,CM獲取下行信息保存最后鎖定的BOOT頻率

24、到NVRAM；掃描下行每 6/8 MHz 間隔 65/88 - 860 MHz。識別 DOCSIS 包PID 0x1FFE。CM獲得與CMTS同步 CMTS廣播下行給所有 CM；CMs讀取CMTS的Timing并調(diào)節(jié)本地時鐘（時鐘最小單位0.98微妙)。(6.25 usec/64=.09765625 usec =1/4 the symbol duration of the highest rate=10.24 MHz),,

25、,CMTS,CM,CM:Sync insertion = 200 msecMax Lost Sync = 600 msec,UCDs,CMTS廣播UCD給所有CM；UCD維護每個CM與CMTS間的通信Initial Maintenance：初始化Request：請求Station Maintenance：站點維護Data-Short/Long：數(shù)據(jù)包大小UCD內(nèi)容：中心頻率通道帶寬調(diào)制方式微時隙大小FEC,,,

26、CM learns all UCDs available and builds a table,UCD insertion = 2 sec maxTimeout-T1 = 5* MAX UCD interval,CMTS,CM,DOCSIS 微時隙,Minislots表示CMTS每處理固定大小字節(jié)的數(shù)據(jù)包需要的byte-time；6.25 usec 為基本單位。增加微時隙時間可選擇：2、4、8、16、32、64和128乘以6.25

27、作為“minislot”。如2×6.25微秒；微時隙的時間：12.5、25、50、100、200、400 and 800微秒。,Example Value,Time TicksBytes per minislotSymbols per byteSymbols per secondMini slots per secondusecs per minislotTicks per minislot,Para

28、meter,6.25 usecs16 bytes42.560 msys40,000254,,,,,,,Upstream Channel Descriptor,CMTS MAC Header FC Type: 3 MAC Specific FC Parm: 1 Management Ehdr: 0 Ehdr off

29、 MAC Parm: 0x00 Reserved Len: 0x0146 HCS: 0x0000,CMTS MAC Management Destination: 01:E0:2F:00:00:01 Source: 00:50:57:00:28:96 Len:

30、 308 DSAP: 0x00 SSAP: 0x00 Control: 0x03 Version: 0x01 Type: 0x02 UCD Reserved: 0x00 Upstream Channel Id: 0x0

31、2 Config Change Count: 0x01 MiniSlot Size: 0x02 Downstream Channel Id:0x01,,Broadcast MAC,UCD Overall Channel TLVs,UCD TLV's: TLV Type/Length: 1/1 Symbol Rate Symbol Rate: 16 (x160

32、 ksym/sec) TLV Type/Length: 2/4 Frequency Upstream Center Freq.:23000000,UCD Burst Attributes,TLV Type/Length: 3/92 Preamble Pattern Preamble data: TLV Type/Length: 4/37 Burst Descriptor IUC:

33、 1 Request Attr Type/Length: 0x01/1 Modulation Type Value: 1 QPSK Attr Type/Length: 0x02/1 Differential Encoding Value: 2 Off Attr Type/Length: 0x0

34、3/2 Preamble Length Value: 64 Attr Type/Length: 0x04/2 Preamble Value Offset Value: 56 Attr Type/Length: 0x05/1 FEC Error Correction Value: 0 Attr Type/

35、Length: 0x06/1 FEC Codeword Info Bytes Value: 16 Attr Type/Length: 0x07/2 Scrambler Seed Value: 338 Attr Type/Length: 0x08/1 Max Burst Size Value: 2

36、 Attr Type/Length: 0x09/1 Guard Time Size Value: 8 Attr Type/Length: 0x0A/1 Last Codeword Length Value: 1 Fixed Attr Type/Length: 0x0B/1 Scrambler on/off Value:

37、 1 On,Bandwidth Allocation - MAP,32 bit elements describing bandwidth into the future. broadcast to all modems Max number of 4096 minislots.,WHO SID [14 bits], may be a broadcast or unicast. WHAT – IUC bur

38、st type [4 bits]RequestInitial MaintenanceStation MaintenanceShort DataLong Data WHEN – Timing offset [14 bits],,,UCDs,,Bandwidth Allocation MAP,,CM,MAP Information Elements,Request IntervalUsed by the CM to send

39、requests to transmit data to the CMTSInitial MaintenanceUsed by new cable modems to join the the networkStation MaintenanceUsed by cable modems to adjust thier HFC and timing parametersShort DataUsed to send data-

40、the length is defined in the maximum transmit burst parameter in the UCD or config file.Long DataUsed to send long data -> maximum transmit burst defined in the UCD or config fileNull IEUse to indicate the end of

41、the MAP,Bandwidth Allocation MAP,CMTS MAC Management Destination: 01:E0:2F:00:00:01 Source: 00:50:57:00:28:96 Len: 30 DSAP: 0x00 SSAP: 0x0

42、0 Control: 0x03 Version: 0x01 Type: 0x03 MAP Reserved: 0x00 Upstream Channel Id: 0x01 UCD Count: 0x05 Number of Elements: 0x02 Reserved

43、: 0x00 Alloc Start Time: 0x0198B778 Ack Time: 0x0198B596 Ranging Backoff Start:0x02 Ranging Backoff End: 0x03 Data Backoff Start: 0x05 Data Backoff End: 0x0A,,Broadcast MAC,

44、MAP Information Elements,MAP Info Elements: SID: 0x0001 IUC: 0x0006 ;Long Data Grant Offset:0x0000 SID: 0x3FF IUC: 0x0001 ;Request Offset: 0x0009 SID: 0x0000 ;Null IE IUC: 0x0007 Offset: 0x009F Frame Check Seq

45、uence: 0x00000000,Ranging,,,Store Temporary SIDand adjust parameters,Allocate temporary SID,Transmit attempts 16,RNG Interval 2 seconds max,T3 timeoutMin 50 msecMax 200 msec,CM,,Initial Ranging,,,,,,,,,,,,,,,,,,,,,,,,

46、,,,,ucd1 ucd 4 …,ucd1 ucd4……,ucd1 ucd4……,picks ucd 1,Scenario 1CMTS hears on port 4Redirects modem to use ucd4in ranging response,,,sends ranging request,Scenario 2CMTS never hears modemModem will timeoutand use uc

47、d4,,sends ranging resp,picks ucd4,rerange,CM,,Ranging Request,Ranging Response,Range Response TLV's: TLV Type/Length: 1/4 Timing Adjust TX Timing offset: 1250 TLV Type/Length: 2/1 Power Level Ad

48、just TX power offset: 24 TLV Type/Length: 3/2 Offset Freq. Adjust TX Frequency offset: 0 TLV Type/Length: 5/1 Ranging Status Ranging Status: 1 Continue UnknownFrame Check Sequence: 0

49、x00000000,Provisioning,,,UCDs,,MAP,,Dynamic Host Configuration Protocol DHCP [RFC 2131]Trivial File Transfer Protocol TFTP RFC [1123]Time-of-day [RFC-868],CM,Dynamic Host Control Protocol,,,,,,DHCP Discover,DHCP Offe

50、r,DHCP request,,,DHCP Ack,DHCP Relay Agent,CM,DHCP Discover,DHCP - Dynamic Host Configuration Protocol DHCP Magic Cookie: 0x63825363 Message Type DHCP Option Option Code: 53 Message Type Option Len

51、gth: 1 Message Type: 1 Discover Client Identifier DHCP Option Option Code: 61 Client Identifier Option Length: 7 Hardware Type: 1 Hardware Address: 00:90:83:37:CA:9C

52、 Parameter Request List DHCP Option Option Code: 55 Parameter Request List Option Length: 5 Requested Option: 1 Subnet Mask Requested Option: 2 Time Offset Requested Option: 3 R

53、outers Requested Option: 4 Time Servers Requested Option: 7 Log Servers Vendor Class Identifier DHCP Option Option Code: 60 Vendor Class Identifier Option Length: 9 Option Data:

54、 DOCSIS 1.0 64 6F 63 73 69 73 31 2E 30 DHCP Option End Option Code: 255 End,DHCP OfferLayer 3-BootP,BootP - Bootstrap Protocol Operation: 2 Boot Reply Hardware Address Ty

55、pe: 1 Ethernet (10Mb) Hardware Address Length: 6 bytes Hops: 0 Transaction ID: 183996391 Seconds Since Boot Start: 0 Flags: 0x0000

56、 IP Address Known By Client: 0.0.0.0 IP Address Not Known By Client Client IP Addr Given By Srvr: 3.3.3.3 Server IP Address: 3.3.3.1 Gateway IP Address: 3.3.3.1 Client Hardware Address:

57、 00:90:83:37:CA:9C Unused: 0x00000000000000000000 Server Host Name: ................ Boot File Name: BASDefaultCMConf 42 41 53 44 65 66 61 75 6C 74 43 4D 43 6F 6E 66 ig1.0.cfg......

58、. 69 67 31 2E 30 2E 63 66 67 00 00 00 00 00 00 00 ................,DHCP OfferApplication Layer,DHCP - Dynamic Host Configuration Protocol DHCP Magic Cookie: 0x63825363 Message TypeDHCP Option Option Code:

59、 53 Message Type Option Length: 1 Message Type: 2 Offer Server IdentifierDHCP Option Option Code: 54 Server Identifier Option Length: 4 Address: 3.3.3.1

60、IP Address Lease TimeDHCP Option Option Code: 51 IP Address Lease Time Option Length: 4 Value: 36000 Subnet MaskDHCP Option Option Code: 1 Subnet Mask Option Length

61、: 4 Address: 255.255.255.0 RoutersDHCP Option Option Code: 3 Routers Option Length: 4 Address: 3.3.3.1 Time ServersDHCP Option Option Code: 4 Time S

62、ervers Option Length: 4 Address: 3.3.3.1 Log ServersDHCP Option Option Code: 7 Log Servers Option Length: 4 Address: 3.3.3.1,DHCP Request,DHCP - Dynamic Host

63、Configuration Protocol DHCP Magic Cookie: 0x63825363 Message TypeDHCP Option Option Code: 53 Message Type Option Length: 1 Message Type: 3 Request Requested IP AddressDHCP

64、 Option Option Code: 50 Requested IP Address Option Length: 4 Address: 3.3.3.3 Server IdentifierDHCP Option Option Code: 54 Server Identifier Option Length: 4

65、 Address: 3.3.3.1 Client IdentifierDHCP Option Option Code: 61 Client Identifier Option Length: 7 Hardware Type: 1 Hardware Address: 00:90:83:37:CA:9C Parameter Request

66、 ListDHCP Option Option Code: 55 Parameter Request List Option Length: 5 Requested Option: 1 Subnet Mask Requested Option: 2 Time Offset Requested Option: 3 Routers Requested

67、 Option: 4 Time Servers Requested Option: 7 Log Servers Vendor Class IdentifierDHCP Option Option Code: 60 Vendor Class Identifier Option Length: 9 Option Data: DOCSIS 1.0 6

68、4 6F 63 73 69 73 31 2E 30 DHCP Option End,DHCP ACK,DHCP - Dynamic Host Configuration Protocol DHCP Magic Cookie: 0x63825363 Message TypeDHCP Option Option Code: 53 Message Type Option Len

69、gth: 1 Message Type: 5 ACK Server IdentifierDHCP Option Option Code: 54 Server Identifier Option Length: 4 Address: 3.3.3.1 IP Address Lease TimeDHCP Option Opt

70、ion Code: 51 IP Address Lease Time Option Length: 4 Value: 36000 Subnet MaskDHCP Option Option Code: 1 Subnet Mask Option Length: 4 Address: 255.255

71、.255.0 RoutersDHCP Option Option Code: 3 Routers Option Length: 4 Address: 3.3.3.1 Time ServersDHCP Option Option Code: 4 Time Servers Option Length: 4 Add