07-12-2012 01:31 AM - edited 03-07-2019 07:44 AM
I setup a network for testing multicast streaming.
It is a non routing environment for unicast, but it is success in multicast.
I check that the multicast source is not present in unicast routing table, how it pass the RPF checking??
on the other word, if there is no routing entry for multicast source in unicast routing table, what is the behavior of RPF checking?
07-12-2012 01:41 AM
Hello,
Correctly, if no matching route for the packet source in the routing table is found, the packet should be dropped because it fails the RPF check.
Can you post a diagram of your topology showing the placement of the sender and receiver, and also show us the contents of the router's routing table? Thank you!
Best regards,
Peter
07-15-2012 08:10 PM
The above is my network diagram.
Since my router is aleady return to others, I can only tell what configuration on each router.
Cisco 1841:
ip multicast-routing
interface f0/0
ip address 192.168.1.1 255.255.255.0
ip pim sparse-mode
ip igmp version 3
interface f0/1
ip address 172.16.0.1 255.255.0.0
ip pim sparse-mode
Cisco 2811:
ip multicast-routing
ip pim bsr-candidate fastethernet 0/1
ip pim rp-candidate fsatethernet 0/1
inferface f0/0
ip address 10.0.0.1 255.0.0.0
ip pim sparse-mode
ip igmp version 3
interface f0/1
ip address 172.16.0.2 255.255.0.0
ip pim sparse-mode
The above is all the configuration besides the default settings. However, it is work and I remeber in the "show ip mroute", I can found the (S,G) route for the source on both router
07-15-2012 08:20 PM
The routing table of the router:
For Cisco 2811:
C 10.0.0.0/8 is directly connected, FastEthernet0/0
C 172.16.0.0/16 is directly connected, FastEthernet0/1
For Cisco 1841:
C 192.168.1.0/24 is directly connected, FastEthernet0/0
C 172.16.0.0/16 is directly connected, FastEthernet0/1
08-13-2014 05:58 AM
I think the catch is 'BSR' configuration in 2811 with candidate RP being Fa0/1.1. 1841 is using (*, 239.1.1.1).
(*, 239.1.1.1), 00:08:12/stopped, RP 172.16.0.2, flags: SJC
Incoming interface: FastEthernet0/1, RPF nbr 172.16.0.2
Outgoing interface list:
FastEthernet0/0, Forward/Sparse, 00:05:24/00:02:05
(10.0.0.2, 239.1.1.1), 00:00:11/00:02:48, flags: J
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
FastEthernet0/0, Forward/Sparse, 00:00:11/00:02:48
07-12-2012 03:16 AM
Hello,
What type of device(s) are you using and what is the topology like? Do you have the "no ip routing" command configured? Understand that on a router, the simple act of configuring an interface creates routes. This type of routes is referred to as connected. Please provide the additional information mentioned above and I will try to help you explain the behavior you see.
Thanks
Anthony
07-15-2012 08:14 PM
I didn't issue the "no ip routing" command and I know the connected routing entry, so I use two router in the test. For the details, you can found my reply on the previous.
07-15-2012 11:18 PM
Hi Tsan,
I can't really see why it would have worked so I labbed it up really quick just to verify. In my environment, I do receive an RPF failure and it does not forward multicast traffic:
Router#show ip mroute 239.0.0.1
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
L - Local, P - Pruned, R - RP-bit set, F - Register flag,
T - SPT-bit set, J - Join SPT, M - MSDP created entry,
X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
U - URD, I - Received Source Specific Host Report,
Z - Multicast Tunnel, z - MDT-data group sender,
Y - Joined MDT-data group, y - Sending to MDT-data group
Outgoing interface flags: H - Hardware switched, A - Assert winner
Timers: Uptime/Expires
Interface state: Interface, Next-Hop or VCD, State/Mode
(*, 239.0.0.1), 00:12:47/00:02:42, RP 172.16.0.2, flags: SJCL
Incoming interface: FastEthernet0/0, RPF nbr 172.16.0.2
Outgoing interface list:
FastEthernet0/1, Forward/Sparse, 00:12:47/00:02:59
(10.0.0.2, 239.0.0.1), 00:00:35/00:02:24, flags: LJ
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
FastEthernet0/1, Forward/Sparse, 00:00:35/00:02:59
Router#show ip rpf 10.0.0.2
RPF information for ? (10.0.0.2) failed, no route exists
Sourcing a ping to a join-group on the router also fails:
Router#ping 239.0.0.1 repeat 10 source 10.0.0.1
Type escape sequence to abort.
Sending 10, 100-byte ICMP Echos to 239.0.0.1, timeout is 2 seconds:
Packet sent with a source address of 10.0.0.1
..........
Router#
So my guess is we are missing something that was overlooked in the configuration or there is a possible defect. I would guess its most likely something we overlooked.
Anthony
07-16-2012 02:18 AM
Hi Anthony,
I have borrow the equipment again and retry the lab, the multicast traffic is success but rpf check is fail in the 1841 router.
I have capture some information (config, routing table, mroute, igmp group, pim and rpf check) in the lab. Is that mean multicast traffic can be pass in some case of rpf fail?
For Cisco 2811:
=~=~=~=~=~=~=~=~=~=~=~= PuTTY log 2012.07.16 16:42:34 =~=~=~=~=~=~=~=~=~=~=~=
Router#ter len 0
Router#sh ver
Cisco IOS Software, 2800 Software (C2800NM-IPBASEK9-M), Version 12.4(9)T5, RELEASE SOFTWARE (fc2)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2007 by Cisco Systems, Inc.
Compiled Thu 16-Aug-07 15:21 by prod_rel_team
ROM: System Bootstrap, Version 12.4(13r)T, RELEASE SOFTWARE (fc1)
Router uptime is 13 minutes
System returned to ROM by power-on
System image file is "flash:c2800nm-ipbasek9-mz.124-9.T5.bin"
This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.
A summary of U.S. laws governing Cisco cryptographic products may be found at:
http://www.cisco.com/wwl/export/crypto/tool/stqrg.html
If you require further assistance please contact us by sending email to
export@cisco.com.
Cisco 2811 (revision 53.51) with 251904K/10240K bytes of memory.
Processor board ID
2 FastEthernet interfaces
DRAM configuration is 64 bits wide with parity enabled.
239K bytes of non-volatile configuration memory.
62720K bytes of ATA CompactFlash (Read/Write)
Configuration register is 0x2102
Router#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
C 172.16.0.0/16 is directly connected, FastEthernet0/1
C 10.0.0.0/8 is directly connected, FastEthernet0/0
Router#ping 192.168.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.1, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
Router#sh ip igmp groups
IGMP Connected Group Membership
Group Address Interface Uptime Expires Last Reporter Group Accounted
239.255.255.250 FastEthernet0/0 00:02:18 00:02:39 10.0.0.2
224.0.1.40 FastEthernet0/1 00:03:27 00:02:09 172.16.0.2
Router#sh ip pim rp
Group: 239.1.1.1, RP: 172.16.0.2, v2, next RP-reachable in 00:01:13
Group: 239.255.255.250, RP: 172.16.0.2, v2, next RP-reachable in 00:01:13
Router#sh ip mroute
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
L - Local, P - Pruned, R - RP-bit set, F - Register flag,
T - SPT-bit set, J - Join SPT, M - MSDP created entry,
X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
U - URD, I - Received Source Specific Host Report,
Z - Multicast Tunnel, z - MDT-data group sender,
Y - Joined MDT-data group, y - Sending to MDT-data group
Outgoing interface flags: H - Hardware switched, A - Assert winner
Timers: Uptime/Expires
Interface state: Interface, Next-Hop or VCD, State/Mode
(*, 239.1.1.1), 00:03:21/00:03:05, RP 172.16.0.2, flags: S
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
FastEthernet0/1, Forward/Sparse, 00:03:21/00:03:05
(10.0.0.2, 239.1.1.1), 00:01:23/00:03:25, flags: T
Incoming interface: FastEthernet0/0, RPF nbr 0.0.0.0
Outgoing interface list:
FastEthernet0/1, Forward/Sparse, 00:01:23/00:03:05
(*, 239.255.255.250), 00:03:22/00:03:05, RP 172.16.0.2, flags: SJC
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
FastEthernet0/0, Forward/Sparse, 00:02:33/00:02:24
FastEthernet0/1, Forward/Sparse, 00:03:22/00:03:05
(*, 224.0.1.40), 00:08:55/00:02:54, RP 0.0.0.0, flags: DCL
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
FastEthernet0/1, Forward/Sparse, 00:03:40/00:02:54
Router#sh ip rpf ?
Hostname or A.B.C.D IP name or address of multicast source
events Triggered RPF events
vrf Select VPN Routing/Forwarding instance
Router#sh ip rpf 10.0.0.2
RPF information for ? (10.0.0.2)
RPF interface: FastEthernet0/0
RPF neighbor: ? (10.0.0.2) - directly connected
RPF route/mask: 10.0.0.0/8
RPF type: unicast (connected)
RPF recursion count: 0
Doing distance-preferred lookups across tables
Router#sh run
Building configuration...
Current configuration : 719 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
!
resource policy
!
!
!
ip cef
!
!
ip multicast-routing
!
!
!
!
!
!
!
interface FastEthernet0/0
ip address 10.0.0.1 255.0.0.0
ip pim sparse-mode
ip igmp version 3
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 172.16.0.2 255.255.0.0
ip pim sparse-mode
duplex auto
speed auto
!
!
ip http server
no ip http secure-server
ip pim bsr-candidate FastEthernet0/1 0
ip pim rp-candidate FastEthernet0/1
!
!
control-plane
!
!
line con 0
line aux 0
line vty 0 4
login
!
scheduler allocate 20000 1000
!
end
Router#
For Cisco 1841:
=~=~=~=~=~=~=~=~=~=~=~= PuTTY log 2012.07.16 16:44:32 =~=~=~=~=~=~=~=~=~=~=~=
ter len 0
Router#sh ver
Cisco IOS Software, 1841 Software (C1841-ADVSECURITYK9-M), Version 12.4(15)T9, RELEASE SOFTWARE (fc5)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2009 by Cisco Systems, Inc.
Compiled Tue 28-Apr-09 11:17 by prod_rel_team
ROM: System Bootstrap, Version 12.4(13r)T, RELEASE SOFTWARE (fc1)
Router uptime is 14 minutes
System returned to ROM by power-on
System image file is "flash:c1841-advsecurityk9-mz.124-15.T9.bin"
This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.
A summary of U.S. laws governing Cisco cryptographic products may be found at:
http://www.cisco.com/wwl/export/crypto/tool/stqrg.html
If you require further assistance please contact us by sending email to
export@cisco.com.
Cisco 1841 (revision 7.0) with 195584K/66560K bytes of memory.
Processor board ID
2 FastEthernet interfaces
1 Serial(sync/async) interface
1 Virtual Private Network (VPN) Module
DRAM configuration is 64 bits wide with parity disabled.
191K bytes of NVRAM.
62720K bytes of ATA CompactFlash (Read/Write)
Configuration register is 0x142
Router#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
C 172.16.0.0/16 is directly connected, FastEthernet0/1
C 192.168.1.0/24 is directly connected, FastEthernet0/0
Router#ping 10.0.0.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.0.0.2, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
Router#sh ip igmp group
IGMP Connected Group Membership
Group Address Interface Uptime Expires Last Reporter Group Accounted
239.1.1.1 FastEthernet0/0 00:05:11 00:02:21 192.168.1.2
239.255.255.250 FastEthernet0/0 00:05:10 00:02:24 192.168.1.2
224.0.1.40 FastEthernet0/1 00:05:13 00:02:22 172.16.0.1
Router#sh ip pim rp
Group: 239.1.1.1, RP: 172.16.0.2, v2, uptime 00:04:59, expires 00:02:09
Group: 239.255.255.250, RP: 172.16.0.2, v2, uptime 00:04:59, expires 00:02:09
Router#sh ip mroute
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
L - Local, P - Pruned, R - RP-bit set, F - Register flag,
T - SPT-bit set, J - Join SPT, M - MSDP created entry,
X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
U - URD, I - Received Source Specific Host Report,
Z - Multicast Tunnel, z - MDT-data group sender,
Y - Joined MDT-data group, y - Sending to MDT-data group
Outgoing interface flags: H - Hardware switched, A - Assert winner
Timers: Uptime/Expires
Interface state: Interface, Next-Hop or VCD, State/Mode
(*, 239.1.1.1), 00:08:12/stopped, RP 172.16.0.2, flags: SJC
Incoming interface: FastEthernet0/1, RPF nbr 172.16.0.2
Outgoing interface list:
FastEthernet0/0, Forward/Sparse, 00:05:24/00:02:05
(10.0.0.2, 239.1.1.1), 00:00:11/00:02:48, flags: J
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
FastEthernet0/0, Forward/Sparse, 00:00:11/00:02:48
(*, 239.255.255.250), 00:08:13/00:02:08, RP 172.16.0.2, flags: SJC
Incoming interface: FastEthernet0/1, RPF nbr 172.16.0.2
Outgoing interface list:
FastEthernet0/0, Forward/Sparse, 00:05:24/00:02:08
(*, 224.0.1.40), 00:08:45/00:02:06, RP 0.0.0.0, flags: DPL
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list: Null
Router#sh ip rpf 10.0.0.2
RPF information for ? (10.0.0.2) failed, no route exists
Router#sh run
Building configuration...
Current configuration : 844 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 25
dot11 syslog
ip cef
!
!
!
!
ip multicast-routing
!
multilink bundle-name authenticated
!
!
!
!
archive
log config
hidekeys
!
!
!
!
!
!
!
interface FastEthernet0/0
ip address 192.168.1.1 255.255.255.0
ip pim sparse-mode
ip igmp version 3
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 172.16.0.1 255.255.0.0
ip pim sparse-mode
duplex auto
speed auto
!
interface Serial0/0/0
no ip address
shutdown
clock rate 2000000
!
ip forward-protocol nd
!
!
no ip http server
no ip http secure-server
!
!
!
!
!
control-plane
!
!
line con 0
line aux 0
line vty 0 4
login
!
scheduler allocate 20000 1000
end
Router#
The multicast source server succesfully stream the film, and cannot ping the client
The multicast client succesfully receive the multicast traffic, and cannot ping the source
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