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1、思科网络学习空间第二期技术讲座IPV6 and Frame format in WLAN,IPV6 Address,IPv4 and IPv6,Currently,there are approximately 1.3 billion usable IPv4 addresses available.,IPv4 and IPv6 Header Comparison,IPv6 Extension Headers,Simpler and more efficient header means:IPv6 has extension headers.It handles the options more
2、 efficiently.It enables faster forwarding rate and end nodes processing.,IPv6 Address Representation,Format:x:x:x:x:x:x:x:x,where x is a 16-bit hexadecimal fieldCase-insensitive for hexadecimal A,B,C,D,E,and FLeading zeros in a field are optional:2031:0:130F:0:0:9C0:876A:130BSuccessive fields of 0 c
3、an be represented as:,but only once per address.Examples:2031:0000:130F:0000:0000:09C0:876A:130B2031:0:130f:9c0:876a:130b2031:130f:9c0:876a:130bincorrectFF01:0:0:0:0:0:0:1 FF01:10:0:0:0:0:0:0:1:10:0:0:0:0:0:0:0:,IPv6 Address Types,Unicast:Address is for a single interfaceIPv6 has several types(for e
4、xample,global,reserved,link-local,and site-local)Multicast:One-to-manyEnables more efficient use of the networkUses a larger address rangeAnycast:One-to-nearest(allocated from unicast address space)Multiple devices share the same addressAll anycast nodes should provide uniform serviceSource devices
5、send packets to anycast addressRouters decide on closest device to reach that destinationSuitable for load balancing and content delivery services,IPv6 Global Unicast Addresses,IPv6 has the same address format for global unicast and for anycast addresses.Uses a global routing prefixa structure that
6、enables aggregation upward,eventually to the ISP.FP=Fomat Prefix(001)TLA ID=Top Level Aggregation Identifer,userd by IANA,INTERNIC etc.NLA ID=Next-Level Aggregation Identifer,used by ISPSLA ID=Site Level Aggrregation Identifer,used by orgnization,EUI-64 to IPv6 Interface Identifier,Inverting the“U(u
7、niversal/local)bitG=individual/group,Anycast,IPv6 has the same address format for global unicast and for anycast addresses.Anycast addresses are allocated from the unicast address spaceWhen a unicast address is assigned to more than one interface,thus turning it into an anycast address,Link-Local Ad
8、dresses,Link-local addresses have a scope limited to the link and are dynamically created on all IPv6 interfaces by using a specific link-local prefix FE80:/10 and a 64-bit interface identifier.Link-local addresses are used for automatic address configuration,neighbor discovery,and router discovery.
9、Link-local addresses are also used by many routing protocols.Link-local addresses can serve as a way to connect devices on the same local network without needing global addresses.When communicating with a link-local address,you must specify the outgoing interface because every interface is connected
10、 to FE80:/10.,Site-Local Addresses,Site-local addresses are designed to be used for addressing inside of a site without the need for a global prefix.Routers must not forward any packets with site-local source or destination addresses outside of the site,1111 1110 11,FEC0:/10,Multicasting,Examples of
11、 Permanent Multicast Addresses,IPv6 Addresses and interface,A single interface may be assigned multiple addresses of any type(unicast,anycast,multicast).Every IPv6-enabled interface contains at least one loopback(:1/128)and one link-local address.Optionally,every interface can have multiple unique l
12、ocal and global addresses.,Router#sh int f0/0FastEthernet0/0 is up,line protocol is up Hardware is AmdFE,address is 000e.38ee.39a0(bia 000e.38ee.39a0)Router(config)#interface fastethernet 0/0Router(config-if)#ipv6 address 2006:1010:0:1:/64 eui-64Router#sh int f0/0FastEthernet0/0 is up,line protocol
13、is up IPv6 is enabled,link-local address is FE80:20E:38FF:FEEE:39A0 Global unicast address(es):2006:1010:0:1:20E:38FF:FEEE:39A0,subnet is 2006:1010:0:1:/64 Joined group address(es):FF02:1 FF02:1:FFEE:39A0 MTU is 1500 bytes,stateless and stateful configuration,Stateless Autoconfiguration,DHCPv6(State
14、ful),DHCPv6 is an updated version of DHCP for IPv4:Supports new addressingEnables more control than stateless autoconfigurationCan be used for renumberingCan be used for automatic domain name registration of hosts using dynamic DNS,DHCPv6 Operation,DHCPv6 operates in a way that is similar to DHCPv4,
15、except:Client first detects the presence of routers on the link.If a router is found,the router advertisement is examined to determine if DHCP can be used.If no router is found,or if the router says DHCP can be used,then:A DHCP solicit message is sent to the all-DHCP-agents multicast address.The cli
16、ent uses the link-local address as the source address.,IPV6 routing protocols,IPv6 Routing Protocols,IPv6 routing types:StaticRIPng(RFC 2080)OSPFv3(RFC 2740)IS-IS for IPv6MP-BGP4(RFC 2545/2858)EIGRP for IPv6The ipv6 unicast-routing command is required to enable IPv6 before any routing protocol is co
17、nfigured.,IPv4-to-IPv6 Transition,Transition richness means:No fixed day to convert;no need to convert all at onceDifferent transition mechanisms are available:Dual stackManual tunnel6to4 tunnelISATAP tunnelTeredo tunnelDifferent compatibility mechanisms:Proxying and translation(NAT-PT),Tunneling is
18、 an integration method in which an IPv6 packet is encapsulated within another protocol,such as IPv4.This method of encapsulation is IPv4.Includes a 20-byte IPv4 header with no options and an IPv6 header and payloadRequires dual-stack routers,IPv6 Tunneling,RIPng for IPv6 Configuration Example,Frame
19、format in Wlan,Data path of wireless client to LAN,AP,Controller,LAN Infrastructure,Switch,LWAPP Discovery broadcast,LWAPP Response,Join Request,Join Response,AP,Controller,LAN Infrastructure,Switch,Vlan,Vlan,Layer 2 LWAPP Mode,LWAPP Discovery,LWAPP Response,Join Request,Join Response,AP,Controller,
20、LAN Infrastructure,Switch,Vlan,Vlan,Layer 3 LWAPP Mode,AP,Controller,LAN Infrastructure,Switch,802.11,802.11+LWAPP,802.1Q,Frames in different phases,AP,802.11,802.11 Frame,Receiver Address:AP radio MAC addressSource Address:client address of sending dataDestination Address:client address of receivin
21、g data,Source:A,Destination:B,IP Header,Source ip:A,Destination ip:B,DATA,AP,LWAPP,LWAPP Frame in Layer 2 mode,MAC Header,LWAPP Header C=0,802.11 frame,CRC,Source MAC Address:AP Destination MAC Address:AP-manage interface address of WLCEtherType=0 x88bb,Source:A,Destination:B,MAC Header,LWAPP Header
22、 C=1,Control,CRC,AP,LWAPP Frame in Layer 2 mode,MAC Header with vlan tag,IP DATA,CRC,Source MAC Address:Source ADestination MAC Address:Destination BSource IP address:ADestination IP address:B,Source:A,Destination:B,AP,LWAPP,LWAPP Frame in Layer 3 mode,MAC Header,IP Header,802.11 frame,CRC,Source MA
23、C Address:AP Destination MAC Address:AP-manage interface address of WLCSource IP Address:APDestination IP addres:AP-manage interface address of WLCSource UDP port number from AP:hash of MAC adressWLC always uses UDP port number:12222 for data and 12223 for control,Source:A,Destination:B,LWAPP Header,UDP Header,Thanks,AP,Controller,
