- Verify that a host maintains at least two routers in its Default Router List and will switch routers when the router in use fails.
TN2 TR1 TR2 HUT
| | | |
| | --> | | RA (multicast)
| | | |
| ------+-------------> | Echo Request (via TR1)
| | | <-- | NS (multicast) [Judgment #1]
| | ------------> | NA
| <-----+-------------- | Echo Reply (via TR1) [Judgment #1]
| | | |
| | | --> | RA (multicast)
| | | |
| ------+-------------> | Echo Request (via TR1)
| <-----+-------------- | Echo Reply (via TR1)
| | | |
| * | | Reachable Time expires
| | | |
| ------+-------------> | Echo Request (via TR1)
| | <------------ | NS [Judgment #2]
| | <------------ | NS
| | <------------ | NS
| | | |
| ------+-------------> | Echo Request (via TR1)
| | | <-- | (multicast) [Judgment #3]
| | | |
V V V V
1. Send RA
IPv6 header
hop limit = 255
source = TR1 (link-local)
destination = all-nodes multicast address
RA
cur hop limit = 64
M = 0
O = 0
router lifetime = 45
reachable time = 10000
retrans timer = 1000
Prefix Information option
prefix length = 64
L = 1
A = 1
valid Lifetime = 2592000
preferred lifetime = 604800
prefix = 3ffe:501:ffff:100::
2. Send Echo Request
IPv6 header
source = TN2 (global)
destination = HUT (global)
Echo Request
3. Observe NS
IPv6 header
hop limit = 255
source = HUT (link-local)
destination = TR1 (solicited-node multicast address)
NS
target = TR1 (link-local)
SLL option
4. Send NA
IPv6 header
hop limit = 255
source = TR1 (link-local)
destination = HUT (link-local)
NA
R = 1
S = 1
O = 1
target = TR1 (link-local)
TLL option
5. Observe Echo Reply
IPv6 header
source = HUT (global)
destination = TN2 (global)
Echo Reply
6. Send RA
IPv6 header
hop limit = 255
source = TR2 (link-local)
destination = all-nodes multicast address
RA
cur hop limit = 64
M = 0
O = 0
router lifetime = 45
reachable time = 10000
retrans timer = 1000
Prefix Information option
prefix length = 64
L = 1
A = 1
valid Lifetime = 2592000
preferred lifetime = 604800
prefix = 3ffe:501:ffff:100::
7. Send Echo Request every 3 seconds for 30 seconds
IPv6 header
source = TN2 (global)
destination = HUT (global)
Echo Request
8. Observe MAX_UNICAST_SOLICIT NSs, when reachable time expires.
IPv6 header
hop limit = 255
source = HUT (link-local)
destination = TR1 (link-local)
NS
target = TR1 (link-local)
SLL option
Node constants:
MAX_UNICAST_SOLICIT: 3 transmissions
9. Send Echo Request
IPv6 header
source = TN2 (global)
destination = HUT (global)
Echo Request
10. Observe MAX_MULTICAST_SOLICIT NSs
IPv6 header
hop limit = 255
source = HUT (link-local)
destination = TR2 (solicited-node multicast address)
NS
target = TR2 (link-local)
SLL option
Node constants:
MAX_MULTICAST_SOLICIT: 3 transmissions
=end html
=head1 JUDGEMENT
=begin html
The Cleanup procedure should cause the NUT to transition Neighbor Cache entries created in this test to state INCOMPLETE and remove any entries from its Default Router and Prefix Lists.
TR1 TR2 HUT
| | |
| --> | | RA
| | |
| | --> | RA
| | |
V V V
1. Send RA
IPv6 header
hop limit = 255
source = TR1 (link-local)
destination = all-nodes multicast address
RA
cur hop limit = 64
M = 0
O = 0
router lifetime = 0
reachable time = 30000
retrans timer = 1000
Prefix Information option
prefix length = 64
L = 1
A = 1
valid Lifetime = 0
preferred lifetime = 0
prefix = 3ffe:501:ffff:100::
2. Send RA
IPv6 header
hop limit = 255
source = TR2 (link-local)
destination = all-nodes multicast address
RA
cur hop limit = 64
M = 0
O = 0
router lifetime = 0
reachable time = 30000
retrans timer = 1000
Prefix Information option
prefix length = 64
L = 1
A = 1
valid Lifetime = 0
preferred lifetime = 0
prefix = 3ffe:501:ffff:100::
=end html
=cut
# =head1 REFERENCE
#
# =begin html
#
#
# 5.3. Garbage Collection and Timeout Requirements
#
#
# The conceptual data structures described above use different
# mechanisms for discarding potentially stale or unused information.
#
#
# From the perspective of correctness there is no need to periodically
# purge Destination and Neighbor Cache entries. Although stale
# information can potentially remain in the cache indefinitely, the
# Neighbor Unreachability Detection algorithm ensures that stale
# information is purged quickly if it is actually being used.
#
#
# To limit the storage needed for the Destination and Neighbor Caches,
# a node may need to garbage-collect old entries. However, care must
# be taken to insure that sufficient space is always present to hold
# the working set of active entries. A small cache may result in an
# excessive number of Neighbor Discovery messages if entries are
# discarded and rebuilt in quick succession. Any LRU-based policy that
# only reclaims entries that have not been used in some time (e.g., ten
# minutes or more) should be adequate for garbage-collecting unused
# entries.
#
#
# A node should retain entries in the Default Router List and the
# Prefix List until their lifetimes expire. However, a node may
# garbage collect entries prematurely if it is low on memory. If not
# all routers are kept on the Default Router list, a node should retain
# at least two entries in the Default Router List (and preferably more)
# in order to maintain robust connectivity for off-link destinations.
#
#
# When removing an entry from the Prefix List there is no need to purge
# any entries from the Destination or Neighbor Caches. Neighbor
# Unreachability Detection will efficiently purge any entries in these
# caches that have become invalid. When removing an entry from the
# Default Router List, however, any entries in the Destination Cache
# that go through that router must perform next-hop determination again
# to select a new default router.
#
#
#
# =end html
#
=pod
=head1 REFERENCE
=begin html