46組播修改ttl實(shí)驗(yàn)

1、組播修改ttl實(shí)驗(yàn)r1是源,所有路由器運(yùn)行ospf并互通,組播接口運(yùn)行pim-dm協(xié)議,r4, r5模擬主機(jī), 并加入組地址224.2.2.2現(xiàn)在ping組地址，收到r4和r5的replyrl#p 224.2.2.2type escape sequenee to abort.sending 1,100-byte icmp echos to 224.2.2.2, timeout is 2 seconds:reply to request 0 from 192.16835.5,176 msreply to request 0 from 192.168.34.4,176 ms在r3上查看pim接口的

2、詳細(xì)信息，發(fā)現(xiàn)默認(rèn)ttl=or3#sh ip pirn in terface sl/1 deseriall/1 is up, line protocol is upinternet address is 192.168.34.3/24multicast switching: fastmulticast packets in/out: 0/6multicast boundary: not setmulticast ttl threshold: 0pim: enabledpim version: 2, mode: densepim dr:0.0.0.0pim neighbor count: 0pi

3、m hello/query interval: 30 secondspim hello packets in/out: 0/13pim state-refresh processing: enabledpim state-refresh origination: disabledpim nbma mode: disabledpim atm multipoint signalling: disabledpim domain border: disabledmulticast tagswitching: disabledr3#sh ip pirn interface f0/0 defastethe

4、rneto/o is up, line protocol is upinternet address is 192.168.35.3/24multicast switching: fastmulticast packets in/out: 0/1multicast boundary: not setmulticast ttl threshold: 0pim: enabledpim version: 2, mode: densepim dr: 192.168.35.3 (this system)pim neighbor count: 0pim hello/query interval: 30 s

5、econdspim hello packets in/out: 0/23pim state-refresh processing: enabledpim state-refresh origination: disabledpim nbma mode: disabledpim atm multipoint signalling: disabledpim domain border: disabledmulticast tagswitching: disabled現(xiàn)在改變r(jià)3上兩個(gè)接口的ttl |'1限，對(duì)于r4的ttl=5,對(duì)于r5的ttl=6r3(config)#int sl/1r3

6、(config-if)#ip multicast ttl-threshold 5r3(config-if)#int f0/0r3(config-if)#ip multicast ttl-threshold 6r1的ping信息，將ttl設(shè)為8發(fā)送，r4和r5都回復(fù)了 reply信息rl#pingprotocol ip:target ip address: 224.2.2.2repeat count 1: 5datagram size 100:timeout in seconds 2:extended commands n: yinterface all:time to live 255: 8t

7、ype of service 0:set df bit in ip header? no:validate reply data? no:data pattern oxabcd:loose, strict, record, timestamp, verbosenone:sweep range of sizes n:type escape sequenee to abortsending 5,100-byte icmp echos to 224.2.2.2, timeout is 2 seconds:reply to request 0 from 192.168.35.5,104 msreply

8、 to request 0 from 192.168.34.4,104 msreply to request 1 from 192.168.34.4,144 msreply to request 1 from 192.168.35.5,160 msreply to request 2 from 192.168.35.5, 92 msreply to request 2 from 192.16834.4,152 msreply to request 3 from 192.168.35.5,116 msreply to request 3 from 192.168.34.4,116 msreply

9、 to request 4 from 192.168.35.5, 76 msreply to request 4 from 192.168.34.4, 76 msr3 ± debug,經(jīng)過(guò)r2 跳后，再進(jìn)行rpf檢測(cè)，ttl從8減到了 6r3(config-if)#no ip mroute-cacher3(config-if)#azr3#debug ip mpacket detailr3#*mar 23 14:32:26.239: ip(0): mac sa=*hdlc* (seriall/0)*mar 23 14:32:26.239: ip(0): ip tos=oxo, len=

10、100z id=79, ttl=6, prot=l*mar 23 14:32:26.243: ip(0): s=192.168.12.1 (seriall/0) d=224.2.2.2 (seriall/1) id=79, prot=l, len=100(100), mforward*mar 23 14:32:26.247: ip(0): s=192.168.12.1 (seriall/0) d=224.2.2.2 (fastetherneto/o) id=79z prot=l, len=100(100), mforward綜上，數(shù)據(jù)包的ttl大于等于門限值則可以轉(zhuǎn)發(fā)。r1的ping信息，將t

11、tl設(shè)為7發(fā)送，只有r4回復(fù)了 reply信息rl#pprotocol ip:target ip address: 224.2.2.2repeat count 1: 5datagram size 100:timeout in seconds 2:extended commands n: yinterface all:time to live 255: 7type of service 0:set df bit in ip header? no:validate reply data? no:data pattern oxabcd:loose, strict, record, timestamp

12、, verbosenone:sweep range of sizes n:type escape sequence to abort.sending 5,100-byte icmp echos to 224.2.2.2, timeout is 2 seconds:reply to request 0 from 192.168.34.4,152 msreply to request 1 from 192.168.34.4,116 msreply to request 2 from 192.168.34.4,116 msreply to request 3 from 192.168.34.4,172 msreply to request 4 from 192.168.34.4, 88 msr3#*mar 23 14:38:09.131: ip(0): mac sa=*hdlc* (seriall/0)*mar 23 14:38:09.131: ip(0): ip tos=0x0, len=100, id=80, ttl=5, prot=l*mar 23 14:38:09.135: ip(0): s=192.168.12.1 (seria