【文章內(nèi)容簡介】 研究生課程 上一頁 下一頁 Types of IPv6 Addresses ? Unicast – Address of a single interface – Delivery to single interface ? Multicast – Address of a set of interfaces – Delivery to all interfaces in the set ? Anycast – Address of a set of interfaces – Delivery to a single interface in the set ? No more broadcast addresses 38 清華大學(xué) 研究生課程 上一頁 下一頁 Address Type Prefixes Address type Binary prefix IPv4patible 0000...0 (96 zero bits) global unicast 001 linklocal unicast 1111 1110 10 sitelocal unicast 1111 1110 11 multicast 1111 1111 ?all other prefixes reserved (approx. 7/8ths of total) ?anycast addresses allocated from unicast prefixes 39 清華大學(xué) 研究生課程 上一頁 下一頁 site topology (16 bits) interface identifier (64 bits) public topology (45 bits) interface ID SLA* NLA* TLA 001 Global Unicast Addresses ? TLA = TopLevel Aggregator NLA* = NextLevel Aggregator(s) SLA* = SiteLevel Aggregator(s) ? all subfields variablelength, nonselfencoding (like CIDR) ? TLAs may be assigned to providers or exchanges 40 清華大學(xué) 研究生課程 上一頁 下一頁 Linklocal addresses for use during autoconfiguration and when no routers are present Sitelocal addresses for independence from changes of TLA / NLA LinkLocal SiteLocal Unicast Addresses 1111111010 0 interface ID 1111111011 0 interface ID SLA* 41 清華大學(xué) 研究生課程 上一頁 下一頁 Interface IDs Lowestorder 64bit field of unicast address may be assigned in several different ways: – autoconfigured from a 64bit EUI64, or expanded from a 48bit MAC address (., Ether address) – autogenerated pseudorandom number (to address privacy concerns) – assigned via DHCP – manually configured – possibly other methods in the future 42 清華大學(xué) 研究生課程 上一頁 下一頁 Some SpecialPurpose Unicast Addresses ? The unspecified address, used as a placeholder when no address is available: 0:0:0:0:0:0:0:0 ? The loopback address, for sending packets to self: 0:0:0:0:0:0:0:1 43 清華大學(xué) 研究生課程 上一頁 下一頁 Multicast Address Format ? flag field – loworder bit indicates permanent/transient group – (three other flags reserved) ? scope field: – 1 node local 8 anizationlocal – 2 linklocal B munitylocal – 5 sitelocal E global – (all other values reserved) ? map IPv6 multicast addresses directly into low order 32 bits of the IEEE 802 MAC FP (8bits) Flags (4bits) Scope (4bits) Group ID (32bits) 11111111 000T Lcl/Sit/Gbl Locally administered RESERVED (80bits) MUST be 0 44 清華大學(xué) 研究生課程 上一頁 下一頁 Outline ?Protocol Background ?Technology Highlights ?Enhanced Capabilities ?Transition Issues ?Next Steps 45 清華大學(xué) 研究生課程 IPv6 Security 46 清華大學(xué) 研究生課程 上一頁 下一頁 IPv6 Security ? All implementations required to support authentication and encryption headers (“ IPsec” ) ? Authentication separate from encryption for use in situations where encryption is prohibited or prohibitively expensive ? Key distribution protocols are under development (independent of IP v4/v6) ? Support for manual key configuration required 47 清華大學(xué) 研究生課程 上一頁 下一頁 Authentication Header ? Destination Address + SPI identifies security association state (key, lifetime, algorithm, etc.) ? Provides authentication and data integrity for all fields of IPv6 packet that do not change enroute ? Default algorithm is Keyed MD5 Next Header Hdr Ext Len Security Parameters Index (SPI) Reserved Sequence Number Authentication Data 48 清華大學(xué) 研究生課程 上一頁 下一頁 Encapsulating Security Payload (ESP) Payload Next Header Security Parameters Index (SPI) Sequence Number Authentication Data Padding Length Padding 49 清華大學(xué) 研究生課程 IPv6 Quality of Service 50 清華大學(xué) 研究生課程 上一頁 下一頁 IP Quality of Service Approaches Two basic approaches developed by IETF: ?“ Integrated Service” (Intserv) – finegrain (perflow), quantitative promises (., x bits per second), uses RSVP signaling ?“ Differentiated Service” (Diffserv) – coarsegrain (perclass), qualitative promises (., higher priority), no explicit signaling 51 清華大學(xué) 研究生課程 上一頁 下一頁 IPv6 Support for IntServ 20bit Flow Label field to identify specific flows needing special QoS – each source chooses its own Flow Label values。 routers use Source Addr + Flow Label to identify distinct flows – Flow Label value of 0 used when no special QoS requested (the mon case today) – this part of IPv6 is not standardized yet, and may well change semantics in the future 52 清華大學(xué) 研究生課程 上一頁 下一頁 IPv6 Support for DiffServ 8bit Traffic Class field to identify specific classes of packets needing special QoS – same as new definition of IPv4 TypeofService byte – may be initialized by source or by router enroute。 may be rewritten by routers enroute – traffic Class value of 0 used when no special QoS requested (the mon case today) 53 清華大學(xué) 研究生課程 上一頁 下一頁 Compromise ?Signaled DiffServ (RFC 2998) – uses RSVP for signaling with coursegrained qualitative aggregate markings – allows for policy control without requiring perrouter state overhead 54 清華大學(xué) 研究生課程 IPv6 Mobility 55 清華大學(xué) 研究生課程 上一頁 下一頁 IPv4 Mobility: Vocabulary home work: permanent “ home” of mobile (., ) permanent address: address in home work, can always be used to reach mobile ., home agent: entity that will perform mobility functions on behalf of mobile, when mobile is remote wide area work 56 清華大學(xué) 研究生課程 上一頁 下一頁 IPv4 Mobility: more vocabulary careofaddress: address in visited work. (., 79,) wide area work visited work: work in which mobile currently resides (., ) permanent