One document matched: draft-hu-pim-route-flap-damping-00.txt
Pim Fangwei. Hu
Internet-Draft Jacni. Qin
Intended status: Standards Track Zheng. Zhang
Expires: April 26, 2012 BenChong. Xu
ZTE Corporation
Oct 24, 2011
PIM Route Flap Damping
draft-hu-pim-route-flap-damping-00.txt
Abstract
This document describes the route flap damping functions for PIM-SM
[RFC4601], to reduce the processing load caused by the instability of
routing peers.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 26, 2012.
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Hu, et al. Expires April 26, 2012 [Page 1]
Internet-Draft PIM Route Flap Damping Oct 2011
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Parameters Definition . . . . . . . . . . . . . . . . . . . . 3
3. PIM Join/Prune message Damping . . . . . . . . . . . . . . . . 3
3.1. (*,*, RP)Join/Prune Message Damping . . . . . . . . . . . 3
3.2. (*, G) Join/Prune Message Damping . . . . . . . . . . . . 7
3.3. (S, G) Join/Prune Message Damping . . . . . . . . . . . . 10
3.4. (S, G, RPT) Join/Prune Message Damping . . . . . . . . . . 14
4. Security Considerations . . . . . . . . . . . . . . . . . . . 17
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6.1. Normative references . . . . . . . . . . . . . . . . . . . 18
6.2. Informative References . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18
Hu, et al. Expires April 26, 2012 [Page 2]
Internet-Draft PIM Route Flap Damping Oct 2011
1. Introduction
The instability of downstream routers, which may include the frequent
change of, for instance the unicast routing, the physical state of
multicast interfaces etc., will trigger an excessive number of Join/
Prune messages sent upwards to the routing peers where an extra
amount of updates of routing state are made. This is referred to
herein as "route flap".
This document specifies the damping functions to reduce the
processing load caused by route flaps on the upstream routers. The
damping functions are categorized according to route flaps resulting
from different types of Join/Prune messages received. In addition,
it should be noted that the original operations and state machines of
the PIM protocol are preserved when the design of these damping
functions is implemented.
2. Parameters Definition
Flap count: It is used to count the times of PIM multicast route item
flapping.
Damping threshold: This value is expressed as a number of PIM
multicast route withdrawals. It is above which a PIM multicast route
will be suppressed.
Damping reuse threshold: This value is expressed as a number of PIM
multicast route withdrawals. It is below which a suppressed item
will now be used again.
Half life timer: It is a cycle timer. When half life timer is
expired, the flap count will be reduced by half if it is bigger than
1. If the flap count is 1, it is reduced to 0. The half life timer
is used in the NoDamping and Damping state.
Maximum hold timer: This value is the maximum time a suppressed PIM
multicast route item should be reuse no matter how unstable it has
been prior to this period of stability.
3. PIM Join/Prune message Damping
3.1. (*,*, RP)Join/Prune Message Damping
The (*,*, RP) Damping state is shown in figure 1, there are three
states:
Hu, et al. Expires April 26, 2012 [Page 3]
Internet-Draft PIM Route Flap Damping Oct 2011
Idle
The damping function isn't enabled yet in this router.
Damping
The (*,*, RP) state is damped in this router. The (*, *, RP)
damping route is in damping list.
NoDamping
The (*,*, RP) state is not damped in this router. The (*, *, RP)
damping route is in damping pending list.
The following events can change the (*,*, RP) Join/Prune message
damping state:
E1: damping function is enabled in the router.
E2: damping disable is disabled in the router.
E3: The flap count is above the damping threshold.
E4: The flap count is below the damping reuse threshold.
E5: maximum hold timer is expired.
(*,*, RP)damping state machine
+------+ E1 +----------+
| Idle |---------------------------> | NoDamping|
+------+ <------------------------- +----------+
^ E2 ^ |
| | |
| | |
E2 | E4 or E5 | |
| | |
| | | E3
| +-------+ | |
+-----------------|Damping|---------+ |
+-------+ <----------+
Figure 1
(*, *, RP) state machine for triggered messages in tabular form:
Hu, et al. Expires April 26, 2012 [Page 4]
Internet-Draft PIM Route Flap Damping Oct 2011
| Event | Idle | Damping | NoDamping |
+-------+---------------+----------------+----------------+
| E1 | ->NoDamping | N/A | N/A |
| | [Action A1] | | |
+-----------------------+----------------+----------------+
| E2 | N/A | -> Idle | -> Idle |
| | | [Action A2] | [Action A2] |
+-----------------------+----------------+----------------+
| | | | -> Damping |
| E3 | N/A | N/A | [Action A3] |
+-----------------------+----------------+----------------+
| E4 | N/A | -> NoDamping | N/A |
| | | [Action A4] | |
+-----------------------+----------------+----------------+
| E5 | N/A | -> NoDamping | N/A |
| | | [Action A5] | |
+-----------------------+----------------+----------------+
Transitions from Idle state
When the (*, *, RP) damping state machine is in Idle state, the
following events may trigger transitions:
E1:The damping function is enabled in this router. The (*, *,
RP)damping state machine enters into NoDamping state
Transitions from NoDamping State
When the (*, *, RP) damping state machine is in NoDamping state,
the following events may trigger transitions:
E3: The flap count is used to count the changes of (*, *, RP)
route. If the (*, *, RP)item is in Join state and the new
Join/Prune message received indicates that the route should be
pruned, the flap count should record the change, and vice
versa, if the (*, *, RP) route is in delete state and new Join/
Prune message received indicates that the route should be
created, the flap count also records it. If the flap count is
above the damping threshold, event E3 is triggered, the state
machine enters into damping state.
Transitions from NoDamping State
When the (*, *, RP) damping state machine is in damping state, the
following events may trigger transitions:
E2: The damping function is disabled in this router. The (*,
*, RP) damping state machine enters into Idle state.
Hu, et al. Expires April 26, 2012 [Page 5]
Internet-Draft PIM Route Flap Damping Oct 2011
E4: The flap count is below the damping reuse threshold, the
item in damping list is reused, and the (*, *, RP) damping
route state machine enters into NoDamping state.
E5: The maximum hold timer is expired. The PIM (*, *, RP)
route item in Damping state is reused no matter how unstable it
has been prior to this period of stability. The (*, *, RP)
damping route state machine enters into NoDamping state.
(*,*, RP) damping state machine actions:
Action A1: The damping function is enabled in the router. The
router is ready to record the times of (*,*, RP) route state
changed. If the PIM Join/Prune message is received and a new
(*,*, RP) item is required to create, the (*,*, RP) item is added
to damping pending list if there is no item for that (*,*, RP) and
the state is Join, and the flap count should plus one. If the PIM
Join/Prune message is received and a (*,*, RP) item is required to
prune from the (*,*, RP) table, the (*,*, RP) item is added to
damping pending list if there is no item for that (*,*, RP) and
the state is Prune, and the flap count should plus one. The half
life timer is started when the (*,*, RP) item is added to the
damping pending list.
The cycle half life timer is running when the damping pending (*,
*, RP) is in NoDamping state. If half life timer is expired, the
flap count is reduced by half.
If the flap count is reduced to zero, (*, *, RP) route should be
recovery based on the state in the damping list. If the state of
(*, *, RP) in the damping pending list is Join, the (*, *, RP)
route will be added to the multicast routing table. If the
damping (*, *, RP) route state in damping list is prune, the (*,
*, RP) route will be deleted from the multicast routing table if
the (*, *, RP) route is existed in. The damping pending (*, *,
RP) is deleted from the damping pending list.
Action A2: The damping function is disabled in the router. The
state machine enters Idle state. The half life timer is stopping
if it runs. The flap count is reset and stop counting the times
of (*,*, RP) route state change.
Action A3: The PIM (*,*, RP) route state is suppressed and moved
from the damping pending list to damping list, and the cycle half
life timer for that (*,*,RP) route is started. The maximum
holding timer is started if it doesn't run.
Hu, et al. Expires April 26, 2012 [Page 6]
Internet-Draft PIM Route Flap Damping Oct 2011
Action A4: The suppressed item is reused again. If the damping
(*,*, RP) route state in damping list is join, the (*,*, RP) route
will be added to the multicast routing table. If the damping
(*,*, RP) route state in damping list is prune, the (*,*, RP)
route will be deleted from the multicast routing table if the
(*,*, RP) route is existed in. The damping (*,*, RP) route is
deleted from the damping list. The flap count is reset and stop
counting the times of (*, *, RP) damping route state change. The
cycle half life timer and maximum hold timer are stopped.
Action A5: The maximum hold timer is expired. The (*,*, RP) route
state item in Damping state is reused. If the damping (*,*, RP)
route state in damping list is join, the (*,*, RP) route will be
added to the multicast routing table. If the damping (*,*, RP)
route state in damping list is prune, the (*,*, RP) route will be
deleted from the multicast routing table if the (*,*, RP) route is
existed in. The reuse timer and maximum hold timer are stopped if
they run. The damping (*,*, RP) route is deleted from the damping
list. The flap count is reset and stop counting the times of (*,
*, RP) damping route state changed. The cycle half life timer and
maximum hold timer are stopped.
3.2. (*, G) Join/Prune Message Damping
The (*, G) Damping state is shown in figure 2, there are three
states:
Idle
The damping function isn't enabled yet in this router
Damping
The (*, G) state is damped in this router. The (*, G) damping
route is in damping list.
NoDamping
The (*, G) state is not damped in this router. The (*, G) damping
route is in damping pending list.
The following events can change the (*, G) Join/Prune message damping
state:
E1: damping function is enabled in the router.
E2: damping disable is disabled in the router.
E3: The flap count is above the damping threshold.
Hu, et al. Expires April 26, 2012 [Page 7]
Internet-Draft PIM Route Flap Damping Oct 2011
E4: The flap count is below the damping reuse threshold
E5: maximum hold timer is expired.
(*,G)damping state machine
+------+ E1 +----------+
| Idle |---------------------------> | NoDamping|
+------+ <------------------------- +----------+
^ E2 ^ |
| | |
| | |
E2 | E4 or E5 | |
| | |
| | | E3
| +-------+ | |
+-----------------|Damping|---------+ |
+-------+ <----------+
Figure 2
(*, G) state machine for triggered messages in tabular form:
| Event | Idle | Damping | NoDamping |
+-------+---------------+----------------+----------------+
| E1 | ->NoDamping | N/A | N/A |
| | [Action A1] | | |
+-----------------------+----------------+----------------+
| E2 | N/A | -> Idle | -> Idle |
| | | [Action A2] | [Action A2] |
+-----------------------+----------------+----------------+
| | | | -> Damping |
| E3 | N/A | N/A | [Action A3] |
+-----------------------+----------------+----------------+
| E4 | N/A | -> NoDamping | N/A |
| | | [Action A4] | |
+-----------------------+----------------+----------------+
| E5 | N/A | -> NoDamping | N/A |
| | | [Action A5] | |
+-----------------------+----------------+----------------+
Transitions from Idle state
When the (*, G) damping state machine is in Idle state, the
following events may trigger transitions:
E1:The damping function is enabled in this router. The (*, G)
damping state machine enters into NoDamping state
Hu, et al. Expires April 26, 2012 [Page 8]
Internet-Draft PIM Route Flap Damping Oct 2011
Transitions from NoDamping State
When the (*, G) damping state machine is in NoDamping state, the
following events may trigger transitions:
E3: The flap count is used to count the changes of (*, G)
route. If the (*, G) item is in Join state and the new Join/
Prune message received indicates that the route should be
pruned, the flap count should record the change, and vice
versa, if the (*, G) route is in delete state and new Join/
Prune message received indicates that the route should be
created, the flap count also records it. If the flap count is
above the damping threshold, event E3 is triggered, the state
machine enters into damping state.
Transitions from NoDamping State
When the (*, G) damping state machine is in damping state, the
following events may trigger transitions:
E2: The damping function is disabled in this router. The (*,
G) damping state machine enters into Idle state.
E4: The flap count is below the damping reuse threshold, the
item in damping list is reused, and the (*, G) damping route
state machine enters into NoDamping state.
E5: The maximum hold timer is expired. The PIM (*, G) route
item in Damping state is reused no matter how unstable it has
been prior to this period of stability. The (*,G)damping route
state machine enters into NoDamping state.
(*, G) damping state machine actions:
Action A1: The damping function is enabled in the router. The
router is ready to record the times of (*, G) route state change.
If the PIM Join/Prune message is received and a new (*, G) item is
required to create, the (*, G) item is added to damping pending
list if there is no item for that (*, G) and the state is Join,
and the flap count should record the change. If the PIM Join/
Prune message is received and a (*, G) item is required to prune
from the (*, G) table, the (*, G) item is added to damping pending
list if there is no item for that (*, G) and the state is Prune,
and the flap count should record the change. The cycle half life
timer is started when the (*, G) item is added to the damping
pending list.
The cycle half life timer is running when the (*, G) is in
NoDamping state. If half life timer is expired, the flap count is
reduced by half.
Hu, et al. Expires April 26, 2012 [Page 9]
Internet-Draft PIM Route Flap Damping Oct 2011
If flap count is reduced to zero, (*, G) route should be recovery
based on the state in the damping list. If the state of (*, G) in
the damping pending list is Join, the (*, G) route will be added
to the multicast routing table. If the damping (*, G) route state
in damping list is prune, the (*, G) route will be deleted from
the multicast routing table if the (*, G) route is existed in.
The damping pending (*, G) is deleted from the damping pending
list.
Action A2: The damping function is disabled in the router. The
state machine enters Idle state. The half life timer is stopping
if it runs. The flap count is reset and stop counting the times
of (*, G) route state flapping.
Action A3: The PIM (*, G) route state is suppressed and moved from
the damping pending list to damping list, and the cycle half life
timer for that (*,G) route is started. The maximum holding timer
is started if it doesn't run.
Action A4: The suppressed item is reused again. If the damping
(*, G) route state in damping list is join, the (*, G) route will
be added to the multicast routing table. If the damping (*, G)
route state in damping list is prune, the (*, G) route will be
deleted from the multicast routing table if the (*, G) route is
existed in. The damping (*, G) route is deleted from the damping
list. The flap count is reset and stop counting the times of (*,
G) damping route state changed. The cycle half life timer and
maximum hold timer are stopped.
Action A5: The maximum hold timer is expired. The (*, G) route
state item in damping state is reused. If the damping (*, G)
route state in damping list is join, the (*, G) route will be
added to the multicast routing table. If the damping (*, G) route
state in damping list is prune, the (*, G) route will be deleted
from the multicast routing table if the (*, G) route is existed
in. The reuse timer and maximum hold timer are stopped if they
run. The (*, G) damping route is deleted from the damping list.
The flap count is reset and stop counting the times of (*, G)
damping route state changed. The cycle half life timer and
maximum hold timer are stopped.
3.3. (S, G) Join/Prune Message Damping
The (S, G) damping state is shown in figure 3, there are three
states:
Hu, et al. Expires April 26, 2012 [Page 10]
Internet-Draft PIM Route Flap Damping Oct 2011
Idle
The damping function isn't enabled yet in this router
Damping
The (S, G) state is damped in this router. The(S, G) damping
route is in damping list.
NoDamping
The (S, G) state is not damped in this router. The(S, G)damping
route is in damping pending list.
The following events can change the (S, G) Join/Prune message damping
state:
E1: damping function is enabled in the router.
E2: damping disable is disabled in the router.
E3: the flap count is above the damping threshold.
E4: the flap count is below the damping reuse threshold.
E5: maximum hold timer is expired.
(S,G)damping state machine
+------+ E1 +----------+
| Idle |---------------------------> | NoDamping|
+------+ <------------------------- +----------+
^ E2 ^ |
| | |
| | |
E2 | E4 or E5 | |
| | |
| | | E3
| +-------+ | |
+-----------------|Damping|---------+ |
+-------+ <----------+
Figure 3
(S, G) state machine for triggered messages in tabular form:
Hu, et al. Expires April 26, 2012 [Page 11]
Internet-Draft PIM Route Flap Damping Oct 2011
| Event | Idle | Damping | NoDamping |
+-------+---------------+----------------+----------------+
| E1 | ->NoDamping | N/A | N/A |
| | [Action A1] | | |
+-----------------------+----------------+----------------+
| E2 | N/A | -> Idle | -> Idle |
| | | [Action A2] | [Action A2] |
+-----------------------+----------------+----------------+
| | | | -> Damping |
| E3 | N/A | N/A | [Action A3] |
+-----------------------+----------------+----------------+
| E4 | N/A | -> NoDamping | N/A |
| | | [Action A4] | |
+-----------------------+----------------+----------------+
| E5 | N/A | -> NoDamping | N/A |
| | | [Action A5] | |
+-----------------------+----------------+----------------+
Transitions from Idle state
When the (S, G) damping state machine is in Idle state, the
following events may trigger transitions:
E1:The damping function is enabled in this router. The (S, G)
damping state machine enters into NoDamping state
Transitions from NoDamping State
When the (S, G) damping state machine is in NoDamping state, the
following events may trigger transitions:
E3: The flap count is used to count the changes of (S, G)
route. If (S, G) item is in join state and new Join/Prune
message received indicates that the route should be pruned, the
flap count should record the change, and vice versa, if the (S,
G) route is in delete state and new Join/Prune message received
indicates that the route should be created, the flap count also
records it. If the flap count is above the damping threshold,
event E3 is triggered, the (S, G) damping state machine enters
into damping state.
Transitions from NoDamping State
When the (S, G) damping state machine is in damping state, the
following events may trigger transitions:
E2: The damping function is disabled in this router. The (S,
G) damping state machine enters into Idle state.
Hu, et al. Expires April 26, 2012 [Page 12]
Internet-Draft PIM Route Flap Damping Oct 2011
E4: The flap count is below the damping reuse threshold, the
item in damping list is reused, and the (S, G) damping state
machine enters into NoDamping state.
E5: The maximum hold timer is expired. The PIM (S, G) route
item in Damping state is reused no matter how unstable it has
been prior to this period of stability. The (S, G) damping
state machine enters into NoDamping state.
(S, G) damping state machine actions:
Action A1: The damping function is enabled in the router. The
router is ready to record the times of (S, G) route state change.
If the PIM Join/Prune message is received and a new(S, G) item is
required to create, the (S, G) item is added to damping pending
list if there is no item for that (S, G) and the state is Join,
and the flap count should record the change. If the PIM Join/
Prune message is received and a (S, G) item is required to prune
from the (S, G) table, the (S, G) item is added to damping pending
list if there is no item for that (S, G) and the state is Prune,
and the flap count also record the change. The cycle half life
timer is started when the (S, G) item is added to the damping
pending list.
The cycle half life timer is running when the damping pending (S,
G) is in NoDamping state. If it is expired, the flap count is
reduced by half.
If the flap count is reduced to zero, (S, G) route should be
recovery based on the state in the damping list, that is, if the
state of (S, G) in the damping pending list is Join, the (S, G)
route will be added to the multicast routing table, otherwise, the
damping (S, G) route state in damping list is prune, the (S, G)
route state will be deleted from the multicast routing table if
the (S, G) route is existed in yet. The damping pending (S, G)
item is deleted from the damping pending list.
Action A2: The damping function is disabled in the router. The
state machine enters into Idle state. The half life timer is
stopping if it runs. The flap count is reset and stop counting
the times of (S, G) route state changed.
Action A3: The PIM (S, G) route state is suppressed and moved from
the damping pending list to damping list, and the cycle half life
timer for that (S,G) route is started. The maximum holding Timer
is started if it doesn't run.
Hu, et al. Expires April 26, 2012 [Page 13]
Internet-Draft PIM Route Flap Damping Oct 2011
Action A4: The suppressed item is reused again. If the damping
(S, G) route state in damping list is Join, the (S, G) route will
be added to the multicast routing table. If the damping (S, G)
route state in damping list is Prune, the (S, G) route will be
deleted from the multicast routing table if the (S, G) route is
existed in. The damping(S, G) route is deleted from the damping
list. The flap count is reset and stop counting the times of (S,
G) damping route state flapping. The cycle half life timer and
maximum hold timer are stopped.
Action A5: The maximum hold timer is expired. The (S, G) route
state item in Damping state is reused. If the damping (S, G)
route state in damping list is Join, the (S, G) route will be
added to the multicast routing table. If the damping (S, G) route
state in damping list is Prune, the (S, G) route will be deleted
from the multicast routing table if the (S, G) route is existed
in. maximum hold timer is stopped if they run. The damping(S, G)
route is deleted from the damping list. The flap count is reset
and stop counting the times of (S, G) damping route state
flapping. The cycle half life timer and maximum hold timer are
stopped.
3.4. (S, G, RPT) Join/Prune Message Damping
The (S, G, RPT) Damping state is shown in figure 4, there are three
states:
Idle
The damping function isn't enabled yet in this router.
Damping
The (S, G, RPT) state is damped in this router. The (S, G, RPT)
damping route is in damping list.
NoDamping
The (S, G, RPT) state is not damped in this router. The (S, G,
RPT) damping route is in damping pending list.
The following events can change the (S, G, RPT) Join/Prune message
damping state:
E1: damping function is enabled in the router.
E2: damping disable is disabled in the router.
E3: the flap count is above the damping threshold.
Hu, et al. Expires April 26, 2012 [Page 14]
Internet-Draft PIM Route Flap Damping Oct 2011
E4: the flap count is below the damping reuse threshold.
E5: maximum hold timer is expired.
(S,G,RPT)damping state machine
+------+ E1 +----------+
| Idle |---------------------------> | NoDamping|
+------+ <------------------------- +----------+
^ E2 ^ |
| | |
| | |
E2 | E4 or E5 | |
| | |
| | | E3
| +-------+ | |
+-----------------|Damping|---------+ |
+-------+ <----------+
Figure 4
(S, G, RPT) state machine for triggered messages in tabular form:
| Event | Idle | Damping | NoDamping |
+-------+---------------+----------------+----------------+
| E1 | ->NoDamping | N/A | N/A |
| | [Action A1] | | |
+-----------------------+----------------+----------------+
| E2 | N/A | -> Idle | -> Idle |
| | | [Action A2] | [Action A2] |
+-----------------------+----------------+----------------+
| | | | -> Damping |
| E3 | N/A | N/A | [Action A3] |
+-----------------------+----------------+----------------+
| E4 | N/A | -> NoDamping | N/A |
| | | [Action A4] | |
+-----------------------+----------------+----------------+
| E5 | N/A | -> NoDamping | N/A |
| | | [Action A5] | |
+-----------------------+----------------+----------------+
Transitions from Idle state
When the (S, G, RPT) damping state machine is in Idle state, the
following events may trigger transitions:
E1:The damping function is enabled in this router. The (S, G,
RPT) damping state machine enters into NoDamping state
Hu, et al. Expires April 26, 2012 [Page 15]
Internet-Draft PIM Route Flap Damping Oct 2011
Transitions from NoDamping State
When the (S, G, RPT) damping state machine is in NoDamping state,
the following events may trigger transitions:
E3: The flap count is used to count the changes of (S, G, RPT)
route. If the (S, G,RPT) item is in Join state and the new
Join/Prune message received indicates that the route should be
pruned, the flap count should record the change, and vice
versa, if the (S, G, RPT) route is in delete state and new
Join/Prune message received indicates that the route should be
created, the flap count also records it. If the flap count is
above the damping threshold, event E3 is triggered, the state
machine enters into damping state.
Transitions from NoDamping State
When the (S, G, RPT) damping state machine is in damping state,
the following events may trigger transitions:
E2: The damping function is disabled in this router. The (S,
G, RPT) damping state machine enters into Idle state.
E4: The flap count is below the damping reuse threshold, the
item in damping list is reused, and the (S, G, RPT) damping
route state machine enters into NoDamping state.
E5: The maximum hold timer is expired. The PIM (S, G, RPT)
route item in Damping state is reused no matter how unstable it
has been prior to this period of stability. The (S,G,
RPT)damping route state machine enters into NoDamping state.
(S, G, RPT) damping state machine actions:
Action A1: The damping function is enabled in the router. The
router is ready to record the times of (S, G, RPT) route state
changed. If the PIM Join/Prune message is received and a new
(S,G,RPT) item is required to create, the (S,G,RPT) item is added
to damping pending list if there is no item for that (S,G,RPT) and
the state is Join, and the flap count should plus one. If the PIM
Join/Prune message is received and a (S,G,RPT) item is required to
prune from the (S,G,RPT) table, the (S,G,RPT) item is added to
damping pending list if there is no item for that (S,G,RPT) and
the state is Prune, and the flap count should plus one. The half
life timer is started when the (S, G, RPT) item is added to the
damping pending list.
The cycle half life timer is running when the damping pending (S,
G, RPT) is in NoDamping state. If half life timer is expired, the
flap count is reduced by half.
Hu, et al. Expires April 26, 2012 [Page 16]
Internet-Draft PIM Route Flap Damping Oct 2011
If flap count is reduced to zero, (S, G, RPT) route should be
recovery based on the state in the damping list. If the state of
(S, G, RPT) in the damping pending list is Join, the (S, G, RPT)
route will be added to the multicast routing table. If the
damping (S, G, RPT) route state in damping list is prune, the (S,
G, RPT) route will be deleted from the multicast routing table if
the (S, G, RPT) route is existed in. The damping pending (S, G,
RPT) is deleted from the damping pending list.
Action A2: The damping function is disabled in the router. The
state machine enters Idle state. The half life timer is stopping
if it runs. The flap count is reset and stop counting the times
of (S, G, RPT) route state change.
Action A3: The PIM (S,G,RPT) route state is suppressed and moved
from the damping pending list to damping list, and the cycle half
life timer for that (S,G, RPT) route is started. The maximum
holding timer is started if it doesn't run.
Action A4: The suppressed item is reused again. If the damping
(S, G, RPT) route state in damping list is join, the (S, G, RPT)
route will be added to the multicast routing table. If the
damping (S, G, RPT) route state in damping list is prune, the (S,
G, RPT) route will be deleted from the multicast routing table if
the (S, G, RPT) route is existed in. The damping (S, G, RPT)
route is deleted from the damping list. The flap count is reset
and stop counting the times of (S, G, RPT) damping route state
flapping. The cycle half life timer and maximum hold timer are
stopped.
Action A5: The maximum hold timer is expired. The (S, G, RPT)
route state item in Damping state is reused. If the damping (S,
G, RPT) route state in damping list is join, the (S, G, RPT) route
will be added to the multicast routing table. If the damping (S,
G, RPT) route state in damping list is prune, the (S, G, RPT)
route will be deleted from the multicast routing table if the (S,
G, RPT) route is existed in. There reuse timer and maximum hold
timer are stopped if they run. The damping(S, G, RPT) route is
deleted from the damping list. The flap count is reset and stop
counting the times of (S, G, RPT) damping route state flapping.
The cycle half life timer and maximum hold timer are stopped.
4. Security Considerations
Hu, et al. Expires April 26, 2012 [Page 17]
Internet-Draft PIM Route Flap Damping Oct 2011
5. Acknowledgements
6. References
6.1. Normative references
[RFC4601] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,
"Protocol Independent Multicast - Sparse Mode (PIM-SM):
Protocol Specification (Revised)", RFC 4601, August 2006.
6.2. Informative References
[RFC2439] Villamizar, C., Chandra, R., and R. Govindan, "BGP Route
Flap Damping", RFC 2439, November 1998.
Authors' Addresses
Fangwei Hu
ZTE Corporation
889 Bibo Road
Shanghai 201203
China
Phone: +86-21-68896273
Email: hu.fangwei@zte.com.cn
Jacni Qin
ZTE Corporation
shanghai
China
Email: jacni@jacni.com
Zheng Zhang
ZTE Corporation
No.68 Zijinghua Rd.Yuhuatai District
Nanjing 210012
China
Email: zhang.zheng@zte.com.cn
Hu, et al. Expires April 26, 2012 [Page 18]
Internet-Draft PIM Route Flap Damping Oct 2011
BenChong Xu
ZTE Corporation
No.68 Zijinghua Rd.Yuhuatai District
Nanjing 210012
China
Email: xu.benchong@zte.com.cn
Hu, et al. Expires April 26, 2012 [Page 19]
| PAFTECH AB 2003-2026 | 2026-04-23 00:43:42 |