HSRP aware PIM

http://lostintransit.se/2015/02/13/hsrp-aware-pim/?doing_wp_cron=1584763838.5805230140686035156250

In environments that require redundancy towards clients, HSRP will normally be running. HSRP is a proven protocol and it works but how do we handle when we have clients that need multicast? What triggers multicast to converge when the Active Router (AR) goes down? The following topology is used:

One thing to notice here is that R3 is the PIM DR even though R2 is the HSRP AR. The network has been setup with OSPF, PIM and R1 is the RP. Both R2 and R3 will receive IGMP reports but only R3 will send PIM Join, due to it being the PIM DR. R3 builds the (*,G) towards the RP:

R3#sh 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, E - Extranet,
       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, 
       G - Received BGP C-Mroute, g - Sent BGP C-Mroute, 
       N - Received BGP Shared-Tree Prune, n - BGP C-Mroute suppressed, 
       Q - Received BGP S-A Route, q - Sent BGP S-A Route, 
       V - RD & Vector, v - Vector, p - PIM Joins on route
Outgoing interface flags: H - Hardware switched, A - Assert winner, p - PIM Join
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 239.0.0.1), 02:54:15/00:02:20, RP 1.1.1.1, flags: SJC
  Incoming interface: Ethernet0/0, RPF nbr 13.13.13.1
  Outgoing interface list:
    Ethernet0/2, Forward/Sparse, 00:25:59/00:02:20

We then ping 239.0.0.1 from the multicast source to build the (S,G):

S1#ping 239.0.0.1 re 3
Type escape sequence to abort.
Sending 3, 100-byte ICMP Echos to 239.0.0.1, timeout is 2 seconds:

Reply to request 0 from 10.0.0.10, 35 ms
Reply to request 1 from 10.0.0.10, 1 ms
Reply to request 2 from 10.0.0.10, 2 ms

The (S,G) has been built:

R3#sh 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, E - Extranet,
       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, 
       G - Received BGP C-Mroute, g - Sent BGP C-Mroute, 
       N - Received BGP Shared-Tree Prune, n - BGP C-Mroute suppressed, 
       Q - Received BGP S-A Route, q - Sent BGP S-A Route, 
       V - RD & Vector, v - Vector, p - PIM Joins on route
Outgoing interface flags: H - Hardware switched, A - Assert winner, p - PIM Join
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 239.0.0.1), 02:57:14/stopped, RP 1.1.1.1, flags: SJC
  Incoming interface: Ethernet0/0, RPF nbr 13.13.13.1
  Outgoing interface list:
    Ethernet0/2, Forward/Sparse, 00:28:58/00:02:50

(41.41.41.10, 239.0.0.1), 00:02:03/00:00:56, flags: JT
  Incoming interface: Ethernet0/0, RPF nbr 13.13.13.1
  Outgoing interface list:
    Ethernet0/2, Forward/Sparse, 00:02:03/00:02:50

The unicast and multicast topology is not currently congruent, this may or may not be important. What happens when R3 fails?

R3(config)#int e0/2
R3(config-if)#sh
R3(config-if)#

No replies to the pings coming in until PIM on R2 detects that R3 is gone and takes over the DR role, this will take between 60 to 90 seconds with the default timers in use.

S1#ping 239.0.0.1 re 100 ti 1
Type escape sequence to abort.
Sending 100, 100-byte ICMP Echos to 239.0.0.1, timeout is 1 seconds:

Reply to request 0 from 10.0.0.10, 18 ms
Reply to request 1 from 10.0.0.10, 2 ms....................................................................
.......
Reply to request 77 from 10.0.0.10, 10 ms
Reply to request 78 from 10.0.0.10, 1 ms
Reply to request 79 from 10.0.0.10, 1 ms
Reply to request 80 from 10.0.0.10, 1 ms

We can increase the DR priority on R2 to make it become the DR.

R2(config-if)#ip pim dr-priority 50  
*Feb 13 12:42:45.900: %PIM-5-DRCHG: DR change from neighbor 10.0.0.3 to 10.0.0.2 on interface Ethernet0/2

HSRP aware PIM is a feature that started appearing in IOS 15.3(1)T and makes the HSRP AR become the PIM DR. It will also send PIM messages from the virtual IP which is useful in situations where you have a router with a static route towards an Virtual IP (VIP). This is how Cisco describes the feature:

HSRP Aware PIM enables multicast traffic to be forwarded through the HSRP active router (AR), allowing PIM to leverage HSRP redundancy, avoid potential duplicate traffic, and enable failover, depending on the HSRP states in the device. The PIM designated router (DR) runs on the same gateway as the HSRP AR and maintains mroute states.

In my topology, I am running HSRP towards the clients, so even though this feature sounds as a perfect fit it will not help me in converging my multicast. Let’s configure this feature on R2:

R2(config-if)#ip pim redundancy HSRP1 hsrp dr-priority 100
R2(config-if)#
*Feb 13 12:48:20.024: %PIM-5-DRCHG: DR change from neighbor 10.0.0.3 to 10.0.0.2 on interface Ethernet0/2

R2 is now the PIM DR, R3 will now see two PIM neighbors on interface E0/2:

R3#sh ip pim nei e0/2
PIM Neighbor Table
Mode: B - Bidir Capable, DR - Designated Router, N - Default DR Priority,
      P - Proxy Capable, S - State Refresh Capable, G - GenID Capable
Neighbor          Interface                Uptime/Expires    Ver   DR
Address                                                            Prio/Mode
10.0.0.1          Ethernet0/2              00:00:51/00:01:23 v2    0 / S P G
10.0.0.2          Ethernet0/2              00:07:24/00:01:23 v2    100/ DR S P G

R2 now has the (S,G) and we can see that it was the Assert winner because R3 was previously sending multicasts to the LAN segment.

R2#sh 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, E - Extranet,
       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, 
       G - Received BGP C-Mroute, g - Sent BGP C-Mroute, 
       N - Received BGP Shared-Tree Prune, n - BGP C-Mroute suppressed, 
       Q - Received BGP S-A Route, q - Sent BGP S-A Route, 
       V - RD & Vector, v - Vector, p - PIM Joins on route
Outgoing interface flags: H - Hardware switched, A - Assert winner, p - PIM Join
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 239.0.0.1), 00:20:31/stopped, RP 1.1.1.1, flags: SJC
  Incoming interface: Ethernet0/0, RPF nbr 12.12.12.1
  Outgoing interface list:
    Ethernet0/2, Forward/Sparse, 00:16:21/00:02:35

(41.41.41.10, 239.0.0.1), 00:00:19/00:02:40, flags: JT
  Incoming interface: Ethernet0/0, RPF nbr 12.12.12.1
  Outgoing interface list:
    Ethernet0/2, Forward/Sparse, 00:00:19/00:02:40, A

What happens when R2’s LAN interface goes down? Will R3 become the DR? And how fast will it converge?

R2(config)#int e0/2
R2(config-if)#sh

HSRP changes to active on R3 but the PIM DR role does not converge until the PIM query interval has expired (3x hellos).

*Feb 13 12:51:44.204: HSRP: Et0/2 Grp 1 Redundancy "hsrp-Et0/2-1" state Standby -> Active
R3#sh ip pim nei e0/2
PIM Neighbor Table
Mode: B - Bidir Capable, DR - Designated Router, N - Default DR Priority,
      P - Proxy Capable, S - State Refresh Capable, G - GenID Capable
Neighbor          Interface                Uptime/Expires    Ver   DR
Address                                                            Prio/Mode
10.0.0.1          Ethernet0/2              00:04:05/00:00:36 v2    0 / S P G
10.0.0.2          Ethernet0/2              00:10:39/00:00:36 v2    100/ DR S P G
R3#
*Feb 13 12:53:02.013: %PIM-5-NBRCHG: neighbor 10.0.0.2 DOWN on interface Ethernet0/2 DR
*Feb 13 12:53:02.013: %PIM-5-DRCHG: DR change from neighbor 10.0.0.2 to 10.0.0.3 on interface Ethernet0/2
*Feb 13 12:53:02.013: %PIM-5-NBRCHG: neighbor 10.0.0.1 DOWN on interface Ethernet0/2 non DR

We lose a lot of packets while waiting for PIM to converge:

S1#ping 239.0.0.1 re 100 time 1
Type escape sequence to abort.
Sending 100, 100-byte ICMP Echos to 239.0.0.1, timeout is 1 seconds:

Reply to request 0 from 10.0.0.10, 5 ms
Reply to request 0 from 10.0.0.10, 14 ms...................................................................
Reply to request 68 from 10.0.0.10, 10 ms
Reply to request 69 from 10.0.0.10, 2 ms

Reply to request 70 from 10.0.0.10, 1 ms

HSRP aware PIM didn’t really help us here… So when is it useful? If we use the following topology instead:

The router R5 has been added and the receiver sits between R5 instead. R5 does not run routing with R2 and R3, only static routes pointing at the RP and the multicast source:

R5(config)#ip route 1.1.1.1 255.255.255.255 10.0.0.1
R5(config)#ip route 41.41.41.0 255.255.255.0 10.0.0.1

Without HSRP aware PIM, the RPF check would fail because PIM would peer with the physical address but R5 sees three neighbors on the segment, where one is the VIP:

R5#sh ip pim nei
PIM Neighbor Table
Mode: B - Bidir Capable, DR - Designated Router, N - Default DR Priority,
      P - Proxy Capable, S - State Refresh Capable, G - GenID Capable
Neighbor          Interface                Uptime/Expires    Ver   DR
Address                                                            Prio/Mode
10.0.0.2          Ethernet0/0              00:03:00/00:01:41 v2    100/ DR S P G
10.0.0.1          Ethernet0/0              00:03:00/00:01:41 v2    0 / S P G
10.0.0.3          Ethernet0/0              00:03:00/00:01:41 v2    1 / S P G

R2 will be the one forwarding multicast during normal conditions due to it being the PIM DR via HSRP state of active router:

R2#sh 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, E - Extranet,
       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, 
       G - Received BGP C-Mroute, g - Sent BGP C-Mroute, 
       N - Received BGP Shared-Tree Prune, n - BGP C-Mroute suppressed, 
       Q - Received BGP S-A Route, q - Sent BGP S-A Route, 
       V - RD & Vector, v - Vector, p - PIM Joins on route
Outgoing interface flags: H - Hardware switched, A - Assert winner, p - PIM Join
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 239.0.0.1), 00:02:12/00:02:39, RP 1.1.1.1, flags: S
  Incoming interface: Ethernet0/0, RPF nbr 12.12.12.1
  Outgoing interface list:
    Ethernet0/2, Forward/Sparse, 00:02:12/00:02:39

Let’s try a ping from the source:

S1#ping 239.0.0.1 re 3
Type escape sequence to abort.
Sending 3, 100-byte ICMP Echos to 239.0.0.1, timeout is 2 seconds:

Reply to request 0 from 20.0.0.10, 1 ms
Reply to request 1 from 20.0.0.10, 2 ms
Reply to request 2 from 20.0.0.10, 2 ms

The ping works and R2 has the (S,G):

R2#sh 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, E - Extranet,
       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, 
       G - Received BGP C-Mroute, g - Sent BGP C-Mroute, 
       N - Received BGP Shared-Tree Prune, n - BGP C-Mroute suppressed, 
       Q - Received BGP S-A Route, q - Sent BGP S-A Route, 
       V - RD & Vector, v - Vector, p - PIM Joins on route
Outgoing interface flags: H - Hardware switched, A - Assert winner, p - PIM Join
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 239.0.0.1), 00:04:18/00:03:29, RP 1.1.1.1, flags: S
  Incoming interface: Ethernet0/0, RPF nbr 12.12.12.1
  Outgoing interface list:
    Ethernet0/2, Forward/Sparse, 00:04:18/00:03:29

(41.41.41.10, 239.0.0.1), 00:01:35/00:01:24, flags: T
  Incoming interface: Ethernet0/0, RPF nbr 12.12.12.1
  Outgoing interface list:
    Ethernet0/2, Forward/Sparse, 00:01:35/00:03:29

What happens when R2 fails?

R2#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R2(config)#int e0/2
R2(config-if)#sh
R2(config-if)#

S1#ping 239.0.0.1 re 200 ti 1
Type escape sequence to abort.
Sending 200, 100-byte ICMP Echos to 239.0.0.1, timeout is 1 seconds:

Reply to request 0 from 20.0.0.10, 9 ms
Reply to request 1 from 20.0.0.10, 2 ms
Reply to request 1 from 20.0.0.10, 11 ms....................................................................
......................................................................
............................................................

The pings time out because when the PIM Join from R5 comes in, R3 does not realize that it should process the Join.

*Feb 13 13:20:13.236: PIM(0): Received v2 Join/Prune on Ethernet0/2 from 10.0.0.5, not to us
*Feb 13 13:20:32.183: PIM(0): Generation ID changed from neighbor 10.0.0.2

As it turns out, the PIM redundancy command must be configured on the secondary router as well for it to process PIM Joins to the VIP.

R3(config-if)#ip pim redundancy HSRP1 hsrp dr-priority 10

After this has configured, the incoming Join will be processed. R3 triggers R5 to send a new Join because the GenID is set in the PIM hello to a new value.

*Feb 13 13:59:19.333: PIM(0): Matched redundancy group VIP 10.0.0.1 on Ethernet0/2 Active, processing the Join/Prune, to us

*Feb 13 13:40:34.043: PIM(0): Generation ID changed from neighbor 10.0.0.1

After configuring this, the PIM DR role converges as fast as HSRP allows. I’m using BFD in this scenario.

The key concept for understanding HSRP aware PIM here is that:

• Initially configuring PIM redundancy on the AR will make it the DR
• PIM redundancy must be configured on the secondary router as well, otherwise it will not process PIM Joins to the VIP
• The PIM DR role does not converge until PIM hellos have timed out, the secondary router will process the Joins though so the multicast will converge

This feature is not very well documented so I hope you have learned a bit from this post how this feature really works. This feature does not work when you have receiver on a HSRP LAN, because the DR role is NOT moved until PIM adjacency expires.

Yoga mudras

Mrit-Sanjeevani Mudra

Bend the index finger and touch the tip on the thumb root, At the same time, touch the tip of the thumb with the tips of middle & ring finger together. Keep the little finger straight. Do it with both the hands.

Time:

15 minutes x 3 times a day 

Benefits:

qThis mudra can be used as first aid when you use it at the first sign of a heart attack. It regulates many heart complications. In an emergency, it is faster than Sorbitate (the most frequently used immediate remedy) under the tongue. This mudra can also be used for the general healing and strengthening of the heart.  It is also used as general pain killer. Heart attacks are an indication that a person's lifestyle must be rethought and planned differently. Apart, it is not only useful at the time of cardiac arrest but also it prevents the possibilities of heart attack. As per my experience, the heart patients, who were (said to be) permanently on medications since years, used this mudra. Within a few days all the medicines they were taking, were stopped.

qThis mudra regulates High Blood Pressure as well as Low Blood Pressure.

qIt regulates the Pulse rate, Nervousness and cholesterol level.

qBeneficial in Asthma, Gastric, Stomachache, Migraine, Acidity and burning sensation.

Surya Mudra

Place the ring finger tip on the thumb root. Rest your thumb over the ring finger. Keep the other fingers straight. Do it with both the hands.

Time:

     15 minutes x twice a day

Benefits:

qAs described by the name, it increases heat in the body. It enhances the vital force in the body and makes us active. It is useful for dull and lazy persons.

qIt eliminates cold, cough, sinusitis, diabetes and numbness in arms & legs.

qIt reduces excess fats, swelling, and heaviness from the body thus helpful for reducing weight.

q Surya mudra can cure Liver diseases, Hypo-thyroid and constipation, also controls Blood urea.

qIt regulates the blood circulation and helpful for a glowing skin.

qIt improves the eye sight and cures cataract.

qIt also improves the digestive disorders, BMR (Body Metabolic Rate) and cholesterol.

qIt is helpful in acute headaches and eliminates mental stress.

Kati Mudra

Right Hand: Join the tips of thumb, middle finger and small finger together.

Left Hand: Place the thumb tip on the index nail.

Time:

5 minutes each  x 4 times a day

Benefits:

    This mudra is used for back pain, can be even more effective in a position that relieves the back i.e. lie down on a mat on the floor, and keep both legs on a chair or stool with knee bend at 90 degree as thighs perpendicular with the floor.

MUKUL MUDRA

Join all the four fingers along with the thumb and put your fingertips on the part  of your body that needs more energy. Do this with each hand.

Time:

5 minutes x five times a day

Note:

It should not be done for long time.

Benefits:

qThis mudra gives happiness and good health.

qIt coordinates between body, mind and soul.

qIt improves the physical & inner strength

qIt increases courage and will power.

qIt saves from accidents. Accidents do happen only when there is no coordination between the body & mind.

qIt activates the pituitary gland thus balances the hormones.

q

SURABHI MUDRA

Join the index finger of right hand with the middle finger of left hand. At the same time, join the middle finger of right hand with index finger of left hand. Now, join the ring finger of the right hand with the small finger of the left hand and join the small finger of the right hand with the ring finger of the left hand.  Please keep your thumbs apart and upwards towards the sky. (Please refer the pic)

Note: Don’t touch the thumbs together or with the body.

Time:

10-15 minutes x 3 times a day

Benefits:

qThe Surabhi Mudra is very effective against rheumatism and arthritis.

qIt cures all type of stomach disorders, urinary (excretory) disorders.

qImmense calmness prevails in the mind.

qIn case of extreme tiredness or fatigue, apply Surbhi mudra to boost your energy and stamina.

qIt helps to awaken the kundalini energy.

q It helps to eliminate toxins from the body.

VAYU MUDRA

With each hand, place the index finger tip on the thumb root. Then press the thumb lightly onto the index finger. Keep the other fingers straight in a relaxed position.

Time:

15 minutes x 3 times a day

Benefits:

     This mudra prevents "wind (Vayu)" flatulence, and a sensation of fullness, in all parts of the body. Diseases caused due to wind in the body include Backache, Cervical Spondalitis, Arthritis, Gout  Artharitis , Sciatica, Flatulence, Rheumatism, Parkinson, Paralysis, Angina Pectoris (Heart pain), Polio and trembling in the hands, throat, and head.

SANDHI MUDRA

Right hand: Join the tips of thumb and ring finger together.

Left hand: Join the tips of thumb and middle finger together.

Time:

15 minutes x 3 times a day

Benefits:

     This mudra balances energy in your joints.  Sandhi means joints. It relieves with arthritis or the pain in any joint in the body, whether the pain persist in knee, wrist, shoulder, elbow, ankle, or any other joint. It is beneficial for those who sits or stands in a position the whole day. Along with this mudra it is recommended to do some small exercises to regulate the joints. 

ADITYA MUDRA

Place the thumb tip on the ring finger root with both the hands.

Time:

10 minutes x 3 times a day

Note: Rub the thumb on the ring finger root periodically.

Benefits:

     Aditya Mudra stops sneezing and yang. It is also helpful for those who sneeze a lot, especially after leaving the bed in the morning, sneezing happens one after another for multiple times or some times after sneezing the person suffers with running nose. But everything gets fine after sometime.  Also sometimes sneezing happens due to some allergy (Dust, smoke or smell etc).