15TCP header details (I)source, destination port:16,16 - identify applications at ends of the connectionsequence:32 - indicates 1st data octet in this segmentacknowledgment:32 - next expected sequence number, valid only when the ACK bit (reside in flag) is set
16TCP header details (II) data offset: bit words offset tells the receiver where user data beginsreserved:6 -not usedflag:6URG : validity of urgent pointer fieldACK : validity of acknowledge fieldPSH : push request (pass segment to appl layer immediately)RST : reset the connectionSYN : initial synchronizationFIN : sender at end of byte stream
17TCP header details (III) window:16 - advertise amount of buffer space this node has allocatedchecksum: bits 1’s complement of pseudo header, TCP header and dataurgent pointer:16 - byte position of data that should be processed firstoptions - variable length option e.g. MSS (max segment size) tells destination node
38Broadcast AddressesLayer 2 broadcasts These are sent to all nodes on a LAN.Broadcasts (layer 3) These are sent to all nodes on the network.Unicast These are sent to a single destination host.Multicast These are packets sent from a single source, and transmitted to many devices on different networks.
39Layer 2 broadcasts known as hardware broadcasts they only go out on a LANThe broadcast would be all 1s in binary and all Fs in hexadecimal, as in FF.FF.FF.FF.FF.FF.
40Broadcasts (layer 3)Broadcast messages are meant to reach all hosts on a broadcast domain.example that you’re already familiar with: The network address of would have a broadcast address ofBroadcasts can also be “all networks and all hosts,” as indicated byA good example of a broadcast message is an Address Resolution Protocol (ARP) request.
68Types of IPv6 Addresses Unicast Multicast Anycast single host/one to one (Global, Site-local, Link local)Multicastmultiple host in specified range/one to manyAnycastmultiple host, only received by single host (the nearest host) /one to nearest (unicast)No Broadcast use MulicastEfficient use of the networkRange can be much larger
69Address type identification Unspecified ::/128Loopback ::1/128Link Local FE80::/10Multicast FF00::/8All address types have to support EUI-64 bits interface ID settingExcept for multicast
70IPv6 Global Unicast Addresses IPv6 Global Unicast addresses ถูกออกแบบมาให้เป็นลำดับชั้น เพื่อให้สามารถทำการ aggregate ได้3 bits แรก 001 (2000::/3) คือ IP ชุดแรกที่ IANA ได้รับมาเพื่อให้ใช้กับ IPv6 Unicast
71IPv6 Address Allocation IANA allocated 2001::/16 to IPv6 UnicastRIR gets /23 prefixes from IANARIR allocate /32 prefix to an ISPISP allocate /48 prefix to end customer
72IPv6 Interface IDsLowest order 64-bit field ของ unicast address จะถูกกำหนดได้ด้วยหลายวิธีที่แตกต่างกันAuto-configured from a 64 bit EUI-64Auto-generated random numberDHCPv6Manually configured
73Converting 48-Bit MAC Addresses to IPv6 Modified EUI-64 Identifiers
76The IPv6 header fields are as follows: version (4 bit): Indicates the protocol version, and will thus contain the number 6.DS byte (8 bit): This field is used by the source and routers to identify the packets belonging to the same traffic class and thus distinguish between packets with different priorities.flow label (20 bit): Label for a data flowpayload length (16 bit): Indicates the length of the packet data field.
77The IPv6 header fields are as follows: (2) next header (8 bit): ): Identifies the type of header immediately following the IPv6 header.hop limit (8 bit): Decremented by one by each node that forwards the packet. When the hop limit field reaches zero, the packet is discarded.source address (128 bit): The address of the originator of the packet.destination address ( 128 bit) : The address of the intended recipient of the packet.Reference->http://www.ietf.org/rfc/rfc2460.txt