CCIE's PIM



Multicast Summary:

Why multicast is introduced.

When you want to send a message to some people, unicast based on TCP is too slow, and the broadcast will let everyone know, so the use of multicast, multicast is the use of UDP send, and only one package at a time, only the group members can receive, regardless of whether in a broadcast domain, in addition, the broadcast header in the 4 layer to distinguish it, Multicast can be distinguished at Layer 2 (using the relationship of MAC address and group address)

Unicast can be used as a source and destination

Multicast and broadcast can only be targeted

Advantages of Multicast Protocol: Point-to-multipoint (information acquisition); Point-to-points (c-s)

Disadvantage: Basically the disadvantage of UDP: unreliable, no flow control, disorderly, using RTP in VoIP to ensure; repetitive traffic (must be avoided)

6

S First Hop 3

5 7

1 2 8

4 9 10

Last Hop

R

In the figure above, s go R can be from 1249 to, can also be from 12359,12357109 to, so there will be repetition, in the multicast must be avoided, avoid methods usually have, RPF, declaration, tree structure

RPF: Based on unicast routing work, if S is entered from the left side of the 9, then if the 9 has a route to s on the road by the entry and exports to the above interface, then it has the condition called RPF; RPF election: small ad; small metric; Large interface Address

Disclaimer: If the route of S in the MA network can be reached from two places to the last hop interface, use, such as: If 7 for the last hop,5,7,10 between a switch, then you can use, election: ibid; rule: pim-des: compare to Source, Pim-sm: compare to RP

Tree structure: SPT (source tree), a source tree, source to the recipient's shortest path, there are several sources there are several trees (s,g)

RPT (Shared tree), select RP, all source to RP shortest path, but source to destination is not necessarily shortest path, RP to target shortest path, only one tree, (*,g)

The multicast routing protocol works between first hop and last hop, and is used to forward multicast traffic; s to fist hop using the application software and other means; Last hop to target using IGMP implementations, IGMP confirms that there is a member below

Multicast IPv4 address: Also called flat address---------no mask rule

In general, the first 24 bits of the multicast address are a section, and the last 8 bits are all 0/1 not used

Reserved address:

224.0.0.0--------224.0.0.255 were assigned to each protocol.

224.0.0.1 all router all PCs

224.0.0.2 All Router

224.0.0.3 not assigned

224.0.0.4 DVMRP (Multicast routing protocol)

224.0.0.5/6ospf

224.0.0.9 RIP

224.0.0.10 EIGRP

224.0.0.13PIM (Multicast routing protocol)

Public available address-------224.0.1.0----238.255.255.255 charges apply

232.0.0.0---232.255.255.255 ssm--advanced PIM usage

Glop Address---Send a multicast address 233.0.0.0----233.255.255.255 each request for an as number

such as: as=9999, in the calculation as less than 5 bits in front of 0 (as the total length of 5 bits), then: 09999 is converted to 16---270F, then two bits separated by 0F and then converted to 10 39 in 15, then glop=233.39.15.0-- 233.39.15.255

Private address: 239.0.0.0----239.255.255.255

Multicast MAC Address: Multicast IPv4 address A total of 2^28, theoretical mac also need so much, but when buying a Mac is oui unit, a oui have 2^24 a Mac, you need 2^4 oui, actually only buy half of oui

So the first 25 bits of the Mac are fixed, where the 25th bit from left to right is 0 for multicast, 1 for the other, so 23 bits is required, then the IP address is just 23 added to the Mac (the first 4 bits for the first 25 bits of Mac 4 bit, then 5 bit not), and finally the MAC address

such as: 224.1.1.1-------------01.00.5e.0 0000001 00000001 00000001-----01.00.5e.01.01.01

IGMP works from last to PC, with three versions:

IGMP V1:query,report

IGMP V2:query,report,leave

IGMP V3:query,report,leave, new addition s (source), V3 launched a third mode: SSM; more conducive to business

V2 does not know the source, only to the RP, through the RP to the source

V3 directly to the source, there is no need for RP

60S periodic query, 180Shold time

Cross-layer encapsulation to layer 3

PIM---Protocol-independent multicast, bottom-level regardless of which unicast is available, and BGP has similarities (dependent on IGP work), protocol number: 103,hello:30s hold Time 105S

Three modes: Pim-dem PIM-SM PIM-SSM

Pim-dem: Only source tree, source to target, push mode

1 2 3) 4 5

S FIST R

6

Configuration:

R1----------Interface ethernet0/0

IP address 12.1.1.1 255.255.255.0

No IP route-cache

End

R1#show Run | s IP def

IP Default-gateway 12.1.1.2