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NSP packet Formats

NSP packet Formats. Fred Kuhns Applied Research Laboratory. MSR Internal IP Packet Format. 8 or 16 Bytes. Shim. Ver (4). hlen (4). TOS (8). dgram length (16). Id (16). Flgs (3). Fragment offset (13). TTL (8). Protocol (8). Header checksum (16). IP Header. Source Address (32).

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NSP packet Formats

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  1. NSP packet Formats Fred Kuhns Applied Research Laboratory

  2. MSR Internal IP Packet Format 8 or 16 Bytes Shim Ver (4) hlen (4) TOS (8) dgram length (16) Id (16) Flgs (3) Fragment offset (13) TTL (8) Protocol (8) Header checksum (16) IP Header Source Address (32) Destination Address (32) IP Datagram IP Options ?? IP data (transport header and transport data) AAL5 padding (0 - 40 bytes: Set to Zero) AAL5 Trailer CPCS-UU (0) CPCS-UU (0) Length(IP packet + SHIM) CRC (APIC/FPX calculates and sets)

  3. FPX to SPC – Intra-Port Shim 31 24 19 14 11 1 0 • Input and Output VINs assumed correct. • QID must be in the valid SPC range (1 – 127) • Flag Values • DP (Drop Packet): SPC directive to FPX. Will always be zero coming into SPC. • RC (Reclassify Packet): SPC directive to FPX. May be 0 or 1 going to SPC. SPC must redefine. • NM (No Match): FPX can not classify (no route), FPX to SPC. Set to 0 before returning to FPX. • EX (Exception Packet): Requires non-fast path; IP options, Non IPv4. FPX to SPC. Set to 0 before returning to FPX. • HO (Header Only): FPX to SPC; Set if packet size > 120B and only first chunk sent to SPC. SPC must not modify. SPC can not drop internally if this bit is set. • HR (Header Only Return): Internal FPX flag. SPC must not modify. • FM (From LC/SW): Set by FPX. SPC can use but not modify. • TO (To LC/SW): Set by FPX. SPC can use but not modify. Input VIN Output VIN PPN Flags Queue Identifier (QID) Port # Sub # Port # Sub # Port # DP RC NM EX HO HR FM TO TTL Chunks Queue Length Packet Pointer Second Chunk Pointer

  4. FPX to SPC, Inter-port Shim • Inter-port Shim – expect the Input and Output VINs to be correct. No other information needed – in particular the PPN is not used by the SPC. Likewise, the MTP is not used by the SPC. • PPN : Default value 0x0 • MTP : Default value 0x7f 31 24 19 14 11 3 0 Input VIN Output VIN PPN MTP Flags Port # Sub # Port # Sub # Port #

  5. IP Packets (rfc 791) LLC (AA.AA.03) OUI (00) LLC/ SNAP OUI (00.00) Type (08.00) Version H-length TOS Total length Identification flags Fragment offset TTL protocol Header checksum IP Header Source Address Destination Address IP Datagram Options ?? IP data (transport header and transport data) AAL5 padding (0 - 40 bytes) AAL5 Trailer CPCS-UU (0) CPCS-UU (0) Length (IP packet + LLC/SNAP) CRC

  6. D F M F 0 IP Header Fields (rfc 791) • Version - support IPv4 (4) • Header Length - Length in 32 bit words (>= 5) • TOS - • Total Length - Length of datagram in octets • Id - Assists in reassembling fragments • Flags - • Fragment Offset - Where fragment belongs, offset is in octets • TTL - router must decrement, if 0 then discard packet • Protocol - UDP/TCP/ICMP/RSVP to name a few • Header Checksum - 16 bit one’s complement of the one’s complement sum of all 16 bit words in header • Source Address - Sending hosts IP address • Destination Address - Destination hosts IP address TOS Precedence Field: 111 - Network Control 110 - Internetwork Control 101 - Critic/ECP 100 - Flash Override 011 - Flash 010 - Immediate 001 - Priority 000 - Routine Remaining TOS Fields: D - 1 = Low delay T - 1 = High Throughput R - 1 = High Reliability Prec. D T R 0 0 DF - 1 = Don’t Fragment, MF - 1 = More Fragments

  7. Layout of a UDP Packet Version H-length TOS Total length Identification Flags Fragment offset IP Header TTL Protocol IP Header checksum IP Source Address IP Destination Address Source Port (16) Destination Port (16) UDP header Length (16) UDP Checksum (16) IP Datagram UDP data

  8. Layout of a TCP Packet Version H-length TOS Total length Identification Flags Fragment offset TTL Protocol IP Header checksum IP Header IP Source Address IP Destination Address Source Port (16) Destination Port (16) Sequence Number (32) TCP header Acknowledgment Number (32) IP Datagram hlen (4) Reserved (6) U A P R S F Window Size (16) Checksum (16) Urgent Pointer (16) TCP data

  9. ICMP Version H-length TOS Total length Identification Flags Fragment offset IP Header TTL Protocol IP Header checksum IP Source Address IP Destination Address ICMP header type code checksum IP Datagram ICMP data

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