draft zhangtrillmultilevelsinglenickname00txt Mingui Zhang Donald Eastlake Radia Perlman zhangmingui huaweicom Why multilevel The link state database LSDB is split between the Level 1 L1 areas connected by a Level ID: 350845
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Single Area Border RBridge Nickname for TRILL Multileveldraft-zhang-trill-multilevel-single-nickname-00.txt
Mingui Zhang, Donald
Eastlake, Radia Perlman
zhangmingui
@
huawei.com
Slide2
Why multilevelThe link state database (LSDB) is split between the Level 1 (L1) areas connected by a Level 2 (L2) area so:Each LSDB part is smaller, has less control traffic, and has fewer topology changes.
Optimized routing computation for n
RBridges
is reduced from O(n*log(n)) to O(sqrt(n)*log(n)).Can be specified so as to permit re-use of TRILL nicknames.
March 2015
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TRILL Border RBridge Single NicknameSlide3
TRILL multilevelA major issue of multilevel is on how to manage RBridge nicknames. Alternatives:Unique nicknameGive unique nicknames to all RBridges in all L1/L2 areas.
Aggregated nickname
Assign nicknames independently in each L1 area.
In L2, represent a whole L1 area with one nickname.Single nickname, multiple levels [this document]
The border RBridge nickname is used in both L1, L2Other nicknames in each L1 area are assigned independently.
In L2, represent an L1 area with the list of border nicknames.
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March 2015
TRILL Border RBridge Single NicknameSlide4
Examples4
Area2
RB6,RB7,RB8
RB5
Area1
RB1,RB2,RB3
RB4
L1
L2
L1
RB5
Area15961
RB1,RB2,RB3
RB4
L2
Area15918
RB1,RB2,RB3
L1
RB15961
RB15918
L1
Area{3,30}
RB1,RB2,RB3
Area{2,20}
RB1,RB2,RB3
RB2
L1
L2
L1
RB20
RB3
RB30
Unique
Nicknames
Aggregated
Nicknames
Single
nickname,
Multiple Levels
March 2015
TRILL Border RBridge Single NicknameSlide5
Area discoveryIn L1, border RBridges RB2, RB20 discover each other via L1 LSP exchanging.In L2, an area is represented by the list of border RBridges. The list of border RBridges is announced in L2 LSPs.
Each border RBridge is aware of which RBridges will be used as border RBridges for an area.
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Area{3,30}
RB3
RB30
Area{2,20}
RB2
RB20
LSP
exchange
March 2015
TRILL Border RBridge Single NicknameSlide6
Actions on unicast forwarding6
Area{3,30}
RB3
RB30
Area{2,20}
RB2
RB20
RB44
RB27
MACsrc=S
ingress=RB27
MACdst
=D
egress=RB3
RB27
MACsrc=S
ingress=
RB2
MACdst=D
egress=
RB3/RB30
RB2
MACsrc=S
MACdst=D
egress=
RB44
RB3
ingress=
RB2/RB20
Border RBridge may replace the egress/ingress nickname of the TRILL Data packets.
March 2015
TRILL Border RBridge Single NicknameSlide7
Actions on unicast forwardingNote:The address of a TRILL Data packet is the Inner.MacDA and Inner VLAN or FGL. This address never changes from the initial ingress RBridge
to the final egress
RBridge
. The change in ingress / egress nickname at border RBridges is a little like label swapping.
March 2015
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TRILL Border RBridge Single NicknameSlide8
MAC synchronizationSince the return traffic may go through any border RBridge, all of them need to learn the MAC. The MAC info is synchronized among area border RBridges using L1 ESADI.
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March 2015
TRILL Border RBridge Single NicknameSlide9
Actions on multicast forwarding9
Area{3,30}
RB3
RB30
Area{2,20}
RB2
RB20
RB44
RB27
MACsrc
=S
ingress=RB27
MACdst
=?
egress=RB27(root)
RB27
MACsrc=S
ingress=RB2
MACdst
=?
egress=RB2(root)
RB2
MACsrc=S
MACdst
=?
egress=RB44(root)
RB3
ingress=
RB2/RB20
M-bit=1
M-bit=1
M-bit=1
RB30
L2 -> L1. Drops the packet to avoid duplication.
Designate an border RBridge for multicast forwarding, according to a pseudorandom algorithm.
Only the DRB can do the transition between L1 and L2.
This avoids packet duplication.
tree1
tree2
tree3
RB20
L1 -> L2. Drops the packet to avoid duplication.
March 2015
TRILL Border RBridge Single NicknameSlide10
Multicast scopingBased on the ingress nickname, a multi-destination packet with an L2 ingress nickname MUST NOT be forwarded back into L2. Otherwise, forwarding loops will occur.
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RB3
RB30
Ingress=RB2
Egress=RB44(root)
RB2
RB20
RB44
March 2015
TRILL Border RBridge Single NicknameSlide11
Border nickname per area
If one border RBridge is connected to multiple areas, this border RBridge needs to obtain nicknames per area.
March 2015
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TRILL Border RBridge Single Nickname
RB52|RB53 Slide12
AdvantagesFewer nicknames usedLess configuration, and less ability to screw up the configurationNo Reverse Path Forwarding Check (RPFC) issue since the border RBridge uses its own nickname
Adequate path split on multiple trees
March 2015
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TRILL Border RBridge Single NicknameSlide13
Please read the draft and comment!Thanks!
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March 2015
TRILL Border RBridge Single Nickname