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1 Version 3 Page Topic/Header Ethernet II 4 ARP 5 IP 6 ICMP 7 UDP TCP 9 RIPv1 1 RIPv2 11 RIP authentication 12 EIGRP 13 EIGRP TLVs OSPFv2 25-end OSPFv3 Soon BGPv4 Soon LDP (MPLS) Soon RSVP Soon IGMPv1 Soon IGMPv2 Soon IGMPv3 Soon CGMP Soon PIMv2 Soon MSDP Between x1 and xff, where xff indicates 1 percent reliable link on five minute exponential weighted average Between x1 and xff, where x1 indicated minimally loaded link Specifies network mask bits with RELIABILITY PREFIX LENGTH IP internal Routes TLV BIT Type = x2 MTU 24 LOAD Bits Next hop DELAY BANDWITH BIT Length RESERVED DESTINATION 24 (* special field used for padding, is depending on prefix) HOP COUNT 3 1 Sum of delay in units of 1 microseconds 24 bit IGRP field has 256 multiplier Soon Soon Soon Soon Syslog SNMPv1 SNMPv2 SNMPv3

2 2.2 BIT 15 BIT Präambel ( bit) Präambel ( bit) Präambel ( bit) Präambel ( bit) IEEE 2.2 / 2.3 (RFC 142) Präambel ( bit) Präambel ( bit) Präambel ( bit) SFD ( bit) Destination MAC Adress Bla bla bla Destination MAC Adress (4 bit) Source MAC Adress Source MAC Adress (4 bit) 24 bit bit Length (2byte) DSAP SSAP 272 bit cntl Org code type // Data (if any) // CRC (4byte od. bit)

3 Ethernet II BIT 15 BIT Präambel ( bit) Präambel ( bit) Präambel ( bit) Präambel ( bit) IEEE 2.2 / 2.3 (RFC 142) Präambel ( bit) Präambel ( bit) Präambel ( bit) Destination MAC Adress ( bit) Starting Frame Delimiter (SFD) 112 bit Bla bla bla Destination MAC Adress (4 bit) Source MAC Adress Source MAC Adress (4 bit) bit Type (2byte) 152 bit bit // Data (if any) // CRC (4byte od. bit) Postamble ( bit)

4 ARP Number Hardware Type 1 Ethernet 3 X.25 4 Proteon ProNET Token Ring 6 IEEE 2 Networks 7 ARCnet 11 Apple LocalTalk 14 SMDS 15 Frame Relay ATM 17 HDLC 1 Fibre Channel 19 ATM 2 Serial Link BIT Hardware type Bits BIT Protocol Type Protocol Type: x IPv4 Hardware address length 4 Protocol Address length 4 Operation Code Operation Sender Hardware address (octets 4-5) Sender Hardware address (octets 3) Target Hardware address (octets -1) 1 ARP request 2 ARP reply 3 Reverse ARP request 4 Reverse ARP reply Inverse ARP request 9 Inverse ARP reply Target Hardware address (octets 2-5) Target IP address

5 IPv4 Delay, Throughput, Reliability, Cost, Unused IP Precedence D T R C TOS U IPv4 ECT = ECT = 1, ECN capable ECT CE = CE = 1, congestion CE Reserved-Bit Don t fragment-bit More fragments Bits 15 BIT BIT IP Version Number Number Version Reserved 1-3 Unassigned 4 Internet Protocol version 4 (IPv4) 5 ST Datagram Mode 6 Simple Internet Protocol (SIP) 6 Internet Protocol version 6 (IPv6) 7 TP/IX P Internet Protocol (PIP) 9 TCP and UDP over Bigger Addresses (TUBA) 1-14 Unassigned 15 Reserved Version 4 header length 4 time to live (TTL) Identification type of service (TOS) Protocol Flags 3 source IP address total length (of packet in bytes) fragment offset 13 header checksum 2 bytes bit Protocol Number Host-to-Host Layer Protocol 1 Internet Control Message Protocol (ICMP) 2 Internet Group Management Protocol (IGMP) 4 IP in IP (encapsulation) 6 Transmission Control Protocol (TCP) 17 User Datagram Protocol (UDP) 45 Inter-Domain Routing Protocol (IDRP) 46 Resource Reservation Protocol (RSVP) 47 Generic Routing Encapsulation (GRE) 54 NBMA Next Hop Resolution Protocol (NHRP) Cisco Internet Gateway Routing Protocol (IGRP) 9 Open Shortest Path First (OSPF) destination IP address Options (if any) // Data (if any) // Options: Loose source routing Packet must pass through that series of IP addresses Strict source routing Packet must pass through exactly that list in order listed Record route each passed through router records its ip address into that field Timestamp Similar to Record route, but router enters an additional timestamp

6 ICMP Bits BIT 15 BIT Type Code Checksum Type Code Name ECHO REPLY 3 - DESTINATION UNREACHABLE 3 Network unreachable 3 1 Host unreachable 3 2 Protocol unreachable 3 3 Port unreachable 3 4 Fragmentation Needed and don t fragment flag is set 3 5 Source route failed 3 6 Destination Network unknown 3 7 Destination Host unknown 3 Source Host Isolated 3 9 Destination Network administratively prohibitated 3 1 Destination Host administratively prohibitated 3 11 Destination Network unreachable for type of service 4 SOURCE QUENCH (deprecated) 5 - REDIRECT 5 Redirect Datagram for the Network (or Subnet) 5 1 Redirect Datagram for the Host 5 2 Redirect Datagram for the Network and Type of Service 5 3 Redirect Datagram for the Host and Type of Service 6 ALTERNATE HOST ADDRESS ECHO 9 ROUTER ADVERTISEMENT 1 ROUTER SELECTION 11 - TIME EXCEEDED 11 Time to Live Exceeded in Transit 11 1 Fragment Reassembly Time Exceeded 12 - PARAMETER PROBLEM 12 Pointer Indicates the error 12 1 Missing a Required option 12 2 Bad Length 13 TIMESTAMP 14 TIMESTAMP REPLY 15 INFORMATION Request (obsolete) INFORMATION Reply (obsolete) 17 Address mask request (near-obsolete) 1 Address mask reply (near-obsolete) 3 - TRACEROUTE Variable fields Depending on ICMP Type

7 UDP BIT 15 BIT source port number destination port number UDP length UDP checksum bytes 64 bit // Data (if any) //

8 TCP BIT 15 BIT Sequence number: - Number of previous segment was Current segment contains 512 bytes of data source port number destination port number Next segment sequence would be: = 156 IF NO RANDOMIZATION IS USED, which would be a bit old school... sequence number acknowledgment number 2 bytes bit If the ack number is not the expected next sequence number, or not the current ack number, TCP knows that the last packet was lost, and will initiate a re-transmit. header length 4 Reserved (6 bits) U R G A C K P S H R S T S Y N F I N window size TCP checksum urgent pointer URG ACK PSH RST SYN FIN CWR ECN-ECE Urgent Acknowledgement Push Reset Synchronise Final Congestion Window Reduced ECN-ECHO Options (if any) // Data (if any) // Maximum Segment Size MSS Padding if required to fill the the multiple of bits of the packet

9 Route Entry RIPv1 Version for RIPv1 is set to 1 1 Request 2 Response Bits BIT 15 BIT Set to 2 for IPv4 Command Version Unused Address Family Identifier Unused IP address Address family for IPv4 = 2 Set to, as exception this only happens if a router requests the full routing table of the opposite router 25x 2 byte = 54 byte per UDP packet, as max RIP packet size is 512 byte Route Entry Address Family Identifier Unused (set to all zeros) Unused (set to all zeros) Metric IP address Unused (set to all zeros) Unused Unused (set to all zeros) Destination of the route Metric Metric Hop count between 1 and

10 Route Entry RIPv2 Version for RIPv2 is set to 2 1 Request 2 Response Set to 2 for IPv4 Bits BIT 15 BIT Set to, as exception this only happens if a router requests the full routing table of the opposite router Command Address Family Identifier Version Unused Route Tag Field used by the administrator to tag external routes, or to ensure the RIP redistributed routes are not being fed back into the RIP process (It was suggested to contain the bit autonomous system number ASN) Address family for IPv4 = 2 Set to, as exception this only happens if a router requests the full routing table of the opposite router 25x 2 byte = 54 byte per UDP packet, as max RIP packet size is 512 byte Route Entry Address Family Identifier IP address Subnet Mask Next Hop Metric IP address Subnet Mask Unused Can be: Host route Subnet Major Network Supports VLSM, variable-length Subnet Masking Within same subnet, if the router advertises another router as best path it will set his IP address. If the sending router is metrically closer it will set the IP address field to... Indicating itself as best Metric between 1 = Inacessible Next Hop Destination of the route Metric Metric Hop count between 1 and

11 Route Entry Authentication Version for RIPv2 is set to 2 RIP authentication 1 Request 2 Response Bits BIT 15 BIT Command Version Unused xffff Authentication type Password (Bytes 3) Password (Bytes 4-7) - Plain Text Passwords - MD5 Checksum Set to 2 for IPv4 Password (Bytes - 11) Set to, as exception this only happens if a router requests the full routing table of the opposite router 25x 2 byte = 54 byte per UDP packet, as max RIP packet size is 512 byte Address Family Identifier Password (Bytes 12-15) IP address Subnet Mask Next Hop Metric Route Tag Field used by the administrator to tag external routes, or to ensure the RIP redistributed routes are not being fed back into the RIP process (It was suggested to contain the bit autonomous system number ASN) Can be: Host route Subnet Major Network Supports VLSM, variable-length Subnet Masking Within same subnet, if the router advertises another router as best path it will set his IP address. If the sending router is metrically closer it will set the IP address field to... Indicating itself as best Metric between 1 = Inacessible

12 Bits Number TLV Type General TLV Types x1 EIGRP Parameters x3 Sequence x4 Software Version x5 Next Multicast Sequence IP Specific TLV Types OPCODE Type 1 Update 3 Query 4 Reply 5 Hello 6 IPX SAP 1 SIA Query 11 SIA Reply BIT 15 BIT Version OPCODE FLAGS CHECKSUM EIGRP Covering the entire EIGRP packet, but excludes the IP header x12 IP Internal Routes x13 IP External Routes AppleTalk Specific TLV Types x22 AppleTalk Internal Routes x23 AppleTalk External Routes x24 AppleTalk Cable Configuration SEQUENCE ACK x1 indicates right-most bit = Init, route entries are first in a new neighbor relationship x2 Conditional Receive bit, used in Reliable Multicasting algorythm. IPX Specific TLV Types Autonomous System Number Used by RTP x32 x33 IPX Internal Routes IPX External Routes TLV (Type, Length, Value fields) IP internal Routes TLV EIGRP Parameter Type Length Value (TLV) Bits BIT 15 BIT Bits BIT 15 BIT Type = x2 Length Type = x1 Length Next hop Sum of delay in units of 1 microseconds 24 bit IGRP field has 256 multiplier K1 K2 K3 K4 DELAY K5 RESERVED HOLD TIME BANDWITH MTU 24 HOP COUNT Between x1 and xff, where xff indicates 1 percent reliable link on five minute exponential weighted average Between x1 and xff, where x1 indicated minimally loaded link RELIABILITY PREFIX LENGTH LOAD RESERVED DESTINATION 24 (* special field used for padding, is depending on prefix) Specifies network mask bits

13 EIGRP IP external Routes TLV Bits BIT 15 BIT Type = x3 Length Next hop ORIGINATING ROUTER IP Address or rather Router-ID of the router that redistributed the external route into EIGRP! ORIGINATING AUTONOMOUS SYSTEM NUMBER ASN of the router originating this route Specifies the protocol from which the external route was learned Code External Protocol x1 IGRP x2 EIGRP x3 Static Route x4 RIP x5 Hello x6 OSPF x7 IS-IS x EGP x9 BGP xa IDRP xb Connected Link RESERVED ARBITRARY TAG EXTERNAL PROTOCOL METRIC DELAY External Protocol ID FLAGS May be used to carry a tag set by a route map Field used when redistributing with IGRP, to track the IGRP metric x1 indicates right-most bit = Init, route entries are first in a new neighbor relationship x2 Conditional Receive bit, used in Reliable Multicasting algorythm. BANDWITH Sum of delay in units of 1 microseconds 24 bit IGRP field has 256 multiplier MTU 24 HOP COUNT RELIABILITY LOAD RESERVED Between x1 and xff, where xff indicates 1 percent reliable link on five minute exponential weighted average PREFIX LENGTH DESTINATION 24 (* special field used for padding, is depending on prefix) Specifies network mask bits Between x1 and xff, where x1 indicated minimally loaded link

14 Area Type Backbone yes yes yes yes yes Non-Backbone Non-stub yes yes yes yes yes OSPFv2 LSA Types Stub yes yes no no no Totally Stubby yes no* no no no Not so stubby yes yes yes no no Type Code Description 1 Hello 2 Database Description 3 Link State Request 4 Link State Update 5 Link State Acknowledgement Bits BIT 15 BIT IP Version Number Number Version Reserved 1-3 Unassigned 4 Internet Protocol version 4 (IPv4) 5 ST Datagram Mode 6 Simple Internet Protocol (SIP) 6 Internet Protocol version 6 (IPv6) 7 TP/IX P Internet Protocol (PIP) 9 TCP and UDP over Bigger Addresses (TUBA) 1-14 Unassigned 15 Reserved Version Checksum Type Router ID Area ID Packet Length Authentication Type Authentication* AuType Authententication Type Null (no authentication) 1 Simple (clear text) Password Authentication 2 Cryptographic (MD5) Checksum Authentication* Packet Data IP Header (protocol 9) OSPF Packet If Authentication type is set to 2: OSPF Packet Header OSPF Packet Data x Key ID Authentication Data Length Packet Type Specific Data LSA LSA LSA Cryptographic Sequence Number LSA Header LSA Data

15 OSPFv2 LSA Header Type Code Description 1 Hello 2 Database Description 3 Link State Request 4 Link State Update 5 Link State Acknowledgement Age in seconds since LSA was originated. Incremented at each router interface it exits. Age also is incremented when it resides in a link-state database. BIT 15 BIT Age Bits Options Type Identifies the portion of the OSPF domain, described by the LSA Link State ID Router ID of the router that originated the LSA Incremented each time a new instance of the LSA is originated. Routers can identify the most recent instance of the LSA Checksum Advertising Router Sequence Number Length IP Header (protocol 9) OSPF Packet OSPF Packet Header OSPF Packet Data Packet Type Specific Data LSA LSA LSA LSA Header LSA Data

16 IP Version Number Number Version Reserved 1-3 Unassigned 4 Internet Protocol version 4 (IPv4) 5 ST Datagram Mode 6 Simple Internet Protocol (SIP) 6 Internet Protocol version 6 (IPv6) 7 TP/IX P Internet Protocol (PIP) 9 TCP and UDP over Bigger Addresses (TUBA) 1-14 Unassigned 15 Reserved Type Code Description 1 Hello 2 Database Description 3 Link State Request 4 Link State Update 5 Link State Acknowledgement Bits BIT 15 BIT OSPFv2 Hello packet Version Type = 1 Packet Length Router ID Area ID Checksum Authentication Type Authentication* AuType Authententication Type Null (no authentication) 1 Simple (clear text) Password Authentication 2 Cryptographic (MD5) Checksum If the received packet does not contain the same mask, the packet will be dropped Authentication* Network Mask Higher the better, wins the DR elections If Authentication type is set to 2: In seconds Hello Interval Options Router Priority Router Dead Interval In seconds, will waite for a hello before declaring the neighbor dead Designated Router The IP or rather router-id of the DR IP Header (protocol 9) OSPF Packet Backup Designated Router The IP or rather router-id of the BDR OSPF Packet Header OSPF Packet Data Neighbor Lists all Router ID s of all neighbors from which the router has received a valid Hello within the past RouterDeadInterval Packet Type Specific Data LSA LSA LSA Neigbor LSA Header LSA Data

17 IP Version Number Number Version Reserved 1-3 Unassigned 4 Internet Protocol version 4 (IPv4) 5 ST Datagram Mode 6 Simple Internet Protocol (SIP) 6 Internet Protocol version 6 (IPv6) 7 TP/IX P Internet Protocol (PIP) 9 TCP and UDP over Bigger Addresses (TUBA) 1-14 Unassigned 15 Reserved BIT 15 BIT Version Type = 2 Bits Router ID Area ID Packet Length OSPFv2 Database Description packet Type Code Description 1 Hello 2 Database Description 3 Link State Request 4 Link State Update 5 Link State Acknowledgement Checksum Authentication* Authentication Type AuType Authententication Type Null (no authentication) 1 Simple (clear text) Password Authentication 2 Cryptographic (MD5) Checksum Authentication* unused Size in byte of the largest IP packet sent out without fragmentation. Interface MTU Options I M MS I-Bit, initial bit = 1 only within the initial packet. Subsequent packets have the I-Bit set to On virtual links set to x DD Sequence Number M-Bit, More bit = 1, indicates that this packet is not the last. The last DD packet sets the M-Bit to. LSA Headers MS-Bit, Master/Slave = 1 indicates it s the sending station is the master. Slave sets MS-Bit = Sequence Number is set by the Master IP Header (protocol 9) OSPF Packet DN-Bit (down-bit) Used with MPLS-based Layer 3 VPNs. Advertised back to a customer network via OSPF, a loop can occur. DN bit is set in type 3,5,7 LSA s DN-Bit can prevent routing loops. Options DN O DC EA N/P MC E MT MT indicates if the router supports Multitopology OSPF (MT-OSPF) (DRAFT) Old version refer to this bit as T-Bit -> was never deployed OSPF Packet Header Packet Type Specific Data OSPF Packet Data LSA LSA LSA LSA Header LSA Data O-Bit indicates originating router supports Opaque (supporting Type 9, 1,11 LSA s) DC-Bit = 1 if originating router supports OSPF over demand circuits EA-Bit indicates if router is capable of receiving and forwarding external Attributes LSA s. E-bit = 1 in all External LSA s and in all LSA s originated int the backbone and non-stub areas. E-bit = for all LSA s originated in a stub area. This bit indicates capability of sending/receiving Type 5 LSA s. MC = 1 if router is capable of forwarding IP multicast packets. This would be used by MOSPF N-bit, only used in Hello packets N-Bit = 1 support for NSSA External N-Bit = will not send/receive NSSA External P-Bit, only used in NSSA External LSA headers Tells the ABR of a not-so-stubby-area to translate type 7 LSA s. (Field is used for two purposes)

18 IP Version Number Number Version Reserved 1-3 Unassigned 4 Internet Protocol version 4 (IPv4) 5 ST Datagram Mode 6 Simple Internet Protocol (SIP) 6 Internet Protocol version 6 (IPv6) 7 TP/IX P Internet Protocol (PIP) 9 TCP and UDP over Bigger Addresses (TUBA) 1-14 Unassigned 15 Reserved Type Code Description 1 Hello 2 Database Description 3 Link State Request 4 Link State Update 5 Link State Acknowledgement Bits BIT 15 BIT OSPFv2 Link state request Version Type = 3 Packet Length Router ID Area ID Checksum Authentication Type LSA Types Type Code Description 1 Router LSA 2 Network LSA 3 Network Summary LSA 4 ASBR Summary LSA 5 AS External LSA 6 Group Membership LSA (Multicast, MOSPF) 7 NSSA External LSA External Attributes LSA 9 Opaque LSA (link-local scope) IPv6 1 Opaque LSA (area-local scope) IPv6 11 Opaque LSA (AS scope) IPv6 Authentication* Authentication* Link State Type Link State ID AuType Authententication Type Null (no authentication) 1 Simple (clear text) Password Authentication 2 Cryptographic (MD5) Checksum Type dependant field Advertising Router IP Header (protocol 9) OSPF Packet Router ID of the router that originated the LSA OSPF Packet Header OSPF Packet Data Link State Type Packet Type Specific Data LSA LSA LSA Link State ID LSA Header LSA Data Advertising Router

19 IP Version Number Number Version Reserved 1-3 Unassigned 4 Internet Protocol version 4 (IPv4) 5 ST Datagram Mode 6 Simple Internet Protocol (SIP) 6 Internet Protocol version 6 (IPv6) 7 TP/IX P Internet Protocol (PIP) 9 TCP and UDP over Bigger Addresses (TUBA) 1-14 Unassigned 15 Reserved Type Code Description 1 Hello 2 Database Description 3 Link State Request 4 Link State Update 5 Link State Acknowledgement Bits BIT 15 BIT OSPFv2 Link state update Version Type = 4 Packet Length Router ID Area ID Checksum Authentication Type Authentication* AuType Authententication Type Null (no authentication) 1 Simple (clear text) Password Authentication 2 Cryptographic (MD5) Checksum Number of LSAs included in this packet Authentication* Number of LSAs IP Header (protocol 9) OSPF Packet Each packet can contain multiple LSAs LSA s OSPF Packet Header OSPF Packet Data Packet Type Specific Data LSA LSA LSA LSA Header LSA Data

20 OSPFv2 Link State Acknowledgement packet IP Version Number Number Version Reserved 1-3 Unassigned 4 Internet Protocol version 4 (IPv4) 5 ST Datagram Mode 6 Simple Internet Protocol (SIP) 6 Internet Protocol version 6 (IPv6) 7 TP/IX P Internet Protocol (PIP) 9 TCP and UDP over Bigger Addresses (TUBA) 1-14 Unassigned 15 Reserved Type Code Description 1 Hello 2 Database Description 3 Link State Request 4 Link State Update 5 Link State Acknowledgement Bits BIT 15 BIT Version Type = 5 Packet Length Router ID Area ID Checksum Authentication Type Authentication* AuType Authententication Type Null (no authentication) 1 Simple (clear text) Password Authentication 2 Cryptographic (MD5) Checksum List of LSA headers Authentication* LSA Headers IP Header (protocol 9) OSPF Packet OSPF Packet Header OSPF Packet Data Packet Type Specific Data LSA LSA LSA LSA Header LSA Data

21 Age in seconds since LSA was originated. Incremented at each router interface it exits. Age also is incremented when it resides in a link-state database. BIT 15 BIT Age Bits Options Type = 1 OSPFv2 Router LSA Identifies the portion of the OSPF domain, described by the LSA Router ID of the router that originated the LSA Incremented each time a new instance of the LSA is originated. Routers can identify the most recent instance of the LSA Checksum Link State ID Advertising Router Sequence Number Length LSA Types Type Code Description 1 Router LSA 2 Network LSA 3 Network Summary LSA 4 ASBR Summary LSA 5 AS External LSA 6 Group Membership LSA (Multicast, MOSPF) 7 NSSA External LSA External Attributes LSA 9 Opaque LSA (link-local scope) IPv6 1 Opaque LSA (area-local scope) IPv6 11 Opaque LSA (AS scope) IPv6 V-Bit, Virtual Link Endpoint bit = 1, if the originating router is and endpoint of at least one virtual link, having the described area as transit area. E-Bit, External-Bit = 1 V E B x Link ID Number of Links Router describes all of the originating router s links, or interfaces if originating router is an ASBR B-Bit, Border bit = 1 If when the originating router is an ABR Link Type Value of Link ID field 1 Neigboring routers s Router ID 2 IP address of the DR s interface 3 IP network or subnet address 4 Neigboring router s Router ID Link Type Value of Link Data field 1 IP address of the originating router s interface to the network * 2 IP address of the originating router s interface to the network 3 Networks IP address or subnet mask 4 MIB-II Ifindex value for the originating router s interface Link Type Connection 1 Point-to-Point to another router 2 Connection to a transit network 3 Connection to a stub network 4 Virtual link Field is no longer supported and set to x Link Type TOS Link Type TOS Number of TOS x Number of TOS x Link Data Link ID Link Data Metric TOS Metric Metric TOS Metric Describes a link Describes a link Cost of the link (interface) IP Header (protocol 9) OSPF Packet Header Packet Type Specific Data OSPF Packet OSPF Packet Data LSA LSA LSA LSA Header LSA Data RFC TOS Value IP header TOS field OSPF TOS encoding Normal Service Minimize Monetary Cost 1 2 Maximize Reliability 1 4 Maximize Througput 1 Minimize Delay 1 Is the metric associated with the specified TOS value

22 OSPFv2 Network LSA DR s interface Age in seconds since LSA was originated. Incremented at each router interface it exits. Age also is incremented when it resides in a link-state database. Router ID of the router that originated the LSA Incremented each time a new instance of the LSA is originated. Routers can identify the most recent instance of the LSA BIT 15 BIT Age Checksum Bits Link State ID Advertising Router Sequence Number Options Length Type = 2 LSA Types Type Code Description 1 Router LSA 2 Network LSA 3 Network Summary LSA 4 ASBR Summary LSA 5 AS External LSA 6 Group Membership LSA (Multicast, MOSPF) 7 NSSA External LSA External Attributes LSA 9 Opaque LSA (link-local scope) IPv6 1 Opaque LSA (area-local scope) IPv6 11 Opaque LSA (AS scope) IPv6 Specifies the subnet mask used on this network Network Mask Attached Router Lists the Router ID s of all routers on the multi-access network that are fully adjacent with the DR. List includes the DR s Router ID Attached Router IP Header (protocol 9) OSPF Packet OSPF Packet Header OSPF Packet Data Packet Type Specific Data LSA LSA LSA LSA Header LSA Data

23 OSPFv2 Network ASBR summary DR s interface Age in seconds since LSA was originated. Incremented at each router interface it exits. Age also is incremented when it resides in a link-state database. Router ID of the router that originated the LSA Incremented each time a new instance of the LSA is originated. Routers can identify the most recent instance of the LSA Type 3: used to advertise the mask of the network BIT 15 BIT Age Checksum Bits Link State ID Advertising Router Sequence Number Network Mask Options Length Type = 3 or 4 LSA Types Type Code Description 1 Router LSA 2 Network LSA 3 Network Summary LSA 4 ASBR Summary LSA 5 AS External LSA 6 Group Membership LSA (Multicast, MOSPF) 7 NSSA External LSA External Attributes LSA 9 Opaque LSA (link-local scope) IPv6 1 Opaque LSA (area-local scope) IPv6 11 Opaque LSA (AS scope) IPv6 Cost of the route Type 4: is set to... as this field has no meaning x Metric TOS TOS METRIC Cisco supports only TOS = x Metric IP Header (protocol 9) OSPF Packet OSPF Packet Header OSPF Packet Data Packet Type Specific Data LSA LSA LSA LSA Header LSA Data

24 Age in seconds since LSA was originated. Incremented at each router interface it exits. Age also is incremented when it resides in a link-state database. BIT 15 BIT Age Bits Options Type = 5 OSPFv2 AS External LSA DR s interface Router ID of the router that originated the LSA Incremented each time a new instance of the LSA is originated. Routers can identify the most recent instance of the LSA Checksum Link State ID Advertising Router Sequence Number Length LSA Types Type Code Description 1 Router LSA 2 Network LSA 3 Network Summary LSA 4 ASBR Summary LSA 5 AS External LSA 6 Group Membership LSA (Multicast, MOSPF) 7 NSSA External LSA External Attributes LSA 9 Opaque LSA (link-local scope) IPv6 1 Opaque LSA (area-local scope) IPv6 11 Opaque LSA (AS scope) IPv6 Subnet mask for the destination being advertised. Network Mask Cost of the route, set by the ASBR If LSA Type 5 default route is announced. This field as well as the Link State ID is set to... E Metric E-Bit, External Metric bit: E-Bit = metric type E1 E-Bit = 1 metric type E2 Advertised destination should be forwarded to. Forwarding Address External Route Tag Can be set by the administrator via route-map If set to..., packets will be forwarded to the originating ASBR E TOS TOS Metric Forwarding Address External Route Tag IP Header (protocol 9) OSPF Packet Network Mask OSPF Packet Header OSPF Packet Data E Metric Packet Type Specific Data LSA LSA LSA Forwarding Address External Route Tag LSA Header LSA Data

25 Age in seconds since LSA was originated. Incremented at each router interface it exits. Age also is incremented when it resides in a link-state database. BIT 15 BIT Age Bits Options Type = 5 OSPFv2 NSSA External DR s interface Router ID of the router that originated the LSA Incremented each time a new instance of the LSA is originated. Routers can identify the most recent instance of the LSA Checksum Link State ID Advertising Router Sequence Number Length LSA Types Type Code Description 1 Router LSA 2 Network LSA 3 Network Summary LSA 4 ASBR Summary LSA 5 AS External LSA 6 Group Membership LSA (Multicast, MOSPF) 7 NSSA External LSA External Attributes LSA 9 Opaque LSA (link-local scope) IPv6 1 Opaque LSA (area-local scope) IPv6 11 Opaque LSA (AS scope) IPv6 Subnet mask for the destination being advertised. Network Mask Cost of the route, set by the ASBR If LSA Type 5 default route is announced. This field as well as the Link State ID is set to... E Metric E-Bit, External Metric bit: E-Bit = metric type E1 E-Bit = 1 metric type E2 Advertised destination should be forwarded to. Forwarding Address External Route Tag Can be set by the administrator via route-map If set to..., packets will be forwarded to the originating ASBR E TOS TOS Metric Forwarding Address External Route Tag Network Mask IP Header (protocol 9) OSPF Packet E Metric OSPF Packet Header OSPF Packet Data Forwarding Address Packet Type Specific Data LSA LSA LSA External Route Tag LSA Header LSA Data

26 OSPFv3 Packet Header 1 Hello 2 Database Description 3 LS Database Request 4 LS Database Update 5 LS Acknowledgement Bits BIT 15 BIT Version == 3 Type Packet Length Router ID Area ID Checksum Instance ID x Instance ID allows several instances to be run on the same interface. Has local significants only

27 1 Hello 2 Database Description 3 LS Database Request 4 LS Database Update 5 LS Acknowledgement OSPFv3 Hello Packet Bits BIT 15 BIT Version == 3 Type == 1 Packet Length Router ID Area ID Instance ID allows several instances to be run on the same interface. Has local significants only Checksum Instance ID x Options 24 DC R N MC E V6 Router Priority Options 24 Supports demand circuits Hello Interval Router Dead Interval Originator is an active router. similar to IS-IS overload bit Designated Router Support for NSSA LSA s Backup Designated Router Support for MOSPF AS-External LSA are flooded. (for formation of stub areas) If set to, link should be excluded from IPv6 routing calculations Neighbor Neighbor

28 OSPFv3 Database Description Packet 1 Hello 2 Database Description 3 LS Database Request 4 LS Database Update 5 LS Acknowledgement Bits BIT 15 BIT Version == 3 Type == 2 Packet Length Router ID Area ID Checksum Instance ID x Options 24 Instance ID allows several instances to be run on the same interface. Has local significants only Interface MTU I M M S DD Sequence Number LSA Headers...

29 OSPFv3 LSA Header U-Bit indicates how a route should handle a LSA if it does not recognize the Code. U-Bit = unknown LSA, to be treated as if link-local flooding scope U-Bit = 1 unknown LSA, stored and flooded as if its understood. S2 S1 Link Local 1 Area 1 AS (routing domain) 1 1 Reserved Link State Type U S2 S1 LSA Function Code BIT 15 BIT Link State Age Bits Link State Type LS Type x21 x22 x23 x24 x25 x26 x27 x2 x29 Name Router LSA Network LSA Inter-Area Prefix LSA Inter-Area Router LSA AS-External-LSA Group Membership LSA Type-7 LSA Link LSA Intra-Area Prefix LSA Link State ID Advertising Router Link State Sequence Number Link State Checksum Length

30 U-Bit indicates how a route should handle a LSA if it does not recognize the Code. U-Bit = unknown LSA, to be treated as if link-local flooding scope U-Bit = 1 unknown LSA, stored and flooded as if its understood. S2 S1 Link Local 1 Area 1 AS (routing domain) 1 1 Reserved Link State Type OSPFv3 Router LSA Bits U S2 S1 LSA Function Code BIT 15 BIT Link State Age Link State ID Link State Type LS Type x21 x22 x23 x24 x25 x26 x27 x2 x29 Name Router LSA Network LSA Inter-Area Prefix LSA Inter-Area Router LSA AS-External-LSA Group Membership LSA Type-7 LSA Link LSA Intra-Area Prefix LSA Advertising Router Link State Sequence Number Link State Checksum Length Type Description 1 Point-to-Point 2 Connection to transit network 3 Reserved 4 Virtual Link W V E B Type Options 24 Metric Specifiecs the outbound cost of the interface Interface ID Value to distinguish from other interfaces on the originating router Neighbor Interface ID Interface ID of their neigbors Neighbor Router ID Type Metric Describes the originating router and its links to neighbors. Interface ID Prefix information is carried in the intra-area prefix lsa. Neighbor Interface ID Neighbor Router ID

31 OSPFv3 Network LSA U-Bit indicates how a route should handle a LSA if it does not recognize the Code. U-Bit = unknown LSA, to be treated as if link-local flooding scope U-Bit = 1 unknown LSA, stored and flooded as if its understood. S2 S1 Link Local 1 Area 1 AS (routing domain) 1 1 Reserved Link State Type U S2 S1 LSA Function Code BIT 15 BIT Link State Age Bits Link State Type LS Type x21 x22 x23 x24 x25 x26 x27 x2 x29 Name Router LSA Network LSA Inter-Area Prefix LSA Inter-Area Router LSA AS-External-LSA Group Membership LSA Type-7 LSA Link LSA Intra-Area Prefix LSA Link State ID Advertising Router Link State Sequence Number Originated by the DR of the segment Link State Checksum Length Options 24 Attached Router Attached Router

32 OSPFv3 inter-area prefix LSA U-Bit indicates how a route should handle a LSA if it does not recognize the Code. U-Bit = unknown LSA, to be treated as if link-local flooding scope U-Bit = 1 unknown LSA, stored and flooded as if its understood. S2 S1 Link Local 1 Area 1 AS (routing domain) 1 1 Reserved Link State Type U S2 S1 LSA Function Code BIT 15 BIT Link State Age Bits Link State Type LS Type x21 x22 x23 x24 x25 x26 x27 x2 x29 Name Router LSA Network LSA Inter-Area Prefix LSA Inter-Area Router LSA AS-External-LSA Group Membership LSA Type-7 LSA Link LSA Intra-Area Prefix LSA Link State ID Advertising Router Link State Sequence Number Link State Checksum Length Metric 24 Prefix Length Prefix Options Address Prefix.... ABR originates a separate inter-area prefix lsa for each IPv6 prefix that must be advertised into an area An ABR can also originate an Inter-Area default route into a stub area.

33 OSPFv3 Inter-area router LSA U-Bit indicates how a route should handle a LSA if it does not recognize the Code. U-Bit = unknown LSA, to be treated as if link-local flooding scope U-Bit = 1 unknown LSA, stored and flooded as if its understood. S2 S1 Link Local 1 Area 1 AS (routing domain) 1 1 Reserved Link State Type U S2 S1 LSA Function Code BIT 15 BIT Link State Age Bits Link State Type LS Type x21 x22 x23 x24 x25 x26 x27 x2 x29 Name Router LSA Network LSA Inter-Area Prefix LSA Inter-Area Router LSA AS-External-LSA Group Membership LSA Type-7 LSA Link LSA Intra-Area Prefix LSA Link State ID Advertising Router Link State Sequence Number Link State Checksum Length Capabilities of the ASBR Options 24 Cost to the ASBR Metric 24 Destination Router ID Is the ASBR RID

34 U-Bit indicates how a route should handle a LSA if it does not recognize the Code. U-Bit = unknown LSA, to be treated as if link-local flooding scope U-Bit = 1 unknown LSA, stored and flooded as if its understood. S2 S1 Link Local 1 Area 1 AS (routing domain) 1 1 Reserved Link State Type U S2 S1 LSA Function Code OSPFv3 AS External LSA BIT 15 BIT Link State Age Bits Link State Type LS Type x21 x22 x23 x24 x25 x26 x27 x2 x29 Name Router LSA Network LSA Inter-Area Prefix LSA Inter-Area Router LSA AS-External-LSA Group Membership LSA Type-7 LSA Link LSA Intra-Area Prefix LSA Link State ID Advertising Router Link State Sequence Number E-flag = 1 metric type 2 E-flag = metric type 1 Link State Checksum Length F-flag = 1 T-flag = 1 forwarding address inluded in LSA external route tag included in the LSA E F T Metric Prefix Length Prefix Options Referenced Link State Type Address Prefix.... Forwarding Address (optional) Next-hop address if F-flag is = 1 External Route Tag (optional) External route tag set to value by admin. Value present if the T-flag is = 1 Referenced Link State ID (optional) Allows the prefix to be included in another LSA

35 U-Bit indicates how a route should handle a LSA if it does not recognize the Code. U-Bit = unknown LSA, to be treated as if link-local flooding scope U-Bit = 1 unknown LSA, stored and flooded as if its understood. S2 S1 Link Local 1 Area 1 AS (routing domain) 1 1 Reserved Link State Type U S2 S1 LSA Function Code OSPFv3 Link LSA BIT 15 BIT Link State Age Bits Link State Type LS Type x21 x22 x23 x24 x25 x26 x27 x2 x29 Name Router LSA Network LSA Inter-Area Prefix LSA Inter-Area Router LSA AS-External-LSA Group Membership LSA Type-7 LSA Link LSA Intra-Area Prefix LSA Link State ID Advertising Router Link State Sequence Number Link State Checksum Length Prefix Options P MC LA NU Router Priority Options 24 Router priority of originating router 12-bit link local address attached to this link Combination fields describes a prefix Prefix Length Prefix Options Link-Local Prefix address Link-Local Prefix address Link-Local Prefix address Number of Prefixes Address Prefix.... x P-Bit propagate-bit = 1 Set on NSSA area prefixes that should be re-advertised at the NSSA area border MC-bit multicast-bit = 1 Prefix should be included in multicast routing calculations LA-bit local address bit = 1 Specifies that the prefix is an interface address of the advertising router Provides originating router s link-local address to all other routers attached to the link NU-bit No Unicast bit = 1 Prefix should be excluded from the unicast route calculations Prefix Length Prefix Options x Address Prefix....

36 U-Bit indicates how a route should handle a LSA if it does not recognize the Code. U-Bit = unknown LSA, to be treated as if link-local flooding scope U-Bit = 1 unknown LSA, stored and flooded as if its understood. S2 S1 Link Local 1 Area 1 AS (routing domain) 1 1 Reserved Link State Type U S2 S1 LSA Function Code OSPFv3 Intra-area prefix LSA BIT 15 BIT Link State Age Bits Link State Type LS Type x21 x22 x23 x24 x25 x26 x27 x2 x29 Name Router LSA Network LSA Inter-Area Prefix LSA Inter-Area Router LSA AS-External-LSA Group Membership LSA Type-7 LSA Link LSA Intra-Area Prefix LSA Link State ID Advertising Router Link State Sequence Number Specifies number of prefixes in the LSA Link State Checksum Number of Prefixes Referenced Link State ID Referenced Advertising Router Length Referenced Link State Type Referenced Link State Type = 1, Then Referenced Link State ID is = And the referenced advertising router is RID of the originating router. If prefixes should be associated with a network LSA then: Reference Link State Type = 2 Referenced Link State ID is interface ID of the links DR and advertising router is the RID of the DR Prefix Length Prefix Options Metric Address Prefix Address Prefix Prefix Length Prefix Options Metric Address Prefix Address Prefix