[c-nsp] OSPF equal cost load balancing
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Wed Aug 30 20:25:25 EDT 2017
Hi Aaron - Apologies, yes, we currently have 2 separate L3 ints of equal cost between the asr920 and me3600 Just relying on ospf to do the load balancing) - This is not working particularly well 😊
sho ip route x.x.x.x will only provide loop of next hop (As we use RRs), so Ive included sh ip cef exact route instead:
From ASR920 :
#sho ip cef exact-route XXX.XXX.66.210 YYY.YYY.229.193
XXX.XXX.66.210 -> YYY.YYY.229.193 => label [explicit-null|explicit-null]TAG adj out of GigabitEthernet0/0/22, addr XXX.XXX.67.152
#sho ip cef exact-route XXX.XXX.66.210 YYY.YYY.229.194
XXX.XXX.66.210 -> YYY.YYY.229.194 => label [explicit-null|explicit-null]TAG adj out of GigabitEthernet0/0/23, addr YYY.YYY.230.102
#sh ip arp XXX.XXX.67.152
Protocol Address Age (min) Hardware Addr Type Interface
Internet XXX.XXX.67.152 97 3462.882a.49d7 ARPA GigabitEthernet0/0/22
#sh ip arp YYY.YYY.230.102
Protocol Address Age (min) Hardware Addr Type Interface
Internet YYY.YYY.230.102 3 3462.882a.49d8 ARPA GigabitEthernet0/0/23
...and some more cef output also:
#sh ip cef YYY.YYY.229.193
YYY.YYY.229.192/30
nexthop YYY.YYY.230.102 GigabitEthernet0/0/23 label [explicit-null|explicit-null]
repair: attached-nexthop XXX.XXX.67.152 GigabitEthernet0/0/22
nexthop XXX.XXX.67.152 GigabitEthernet0/0/22 label [explicit-null|explicit-null]
repair: attached-nexthop YYY.YYY.230.102 GigabitEthernet0/0/23
#sh ip cef YYY.YYY.229.193 internal
YYY.YYY.229.192/30, epoch 2, flags [rnolbl, rlbls], RIB[B], refcnt 6, per-destination sharing
sources: RIB
feature space:
IPRM: 0x00018000
Broker: linked, distributed at 4th priority
ifnums:
GigabitEthernet0/0/22(29): XXX.XXX.67.152
GigabitEthernet0/0/23(30): YYY.YYY.230.102
path list 3C293988, 35 locks, per-destination, flags 0x26D [shble, hvsh, rif, rcrsv, hwcn, bgp]
path 3C292714, share 1/1, type recursive, for IPv4
recursive via XXX.XXX.76.211[IPv4:Default], fib 3C9AE64C, 1 terminal fib, v4:Default:XXX.XXX.76.211/32
path list 3D583FF0, 13 locks, per-destination, flags 0x49 [shble, rif, hwcn]
path 3D4A221C, share 0/1, type attached nexthop, for IPv4, flags [has-rpr]
MPLS short path extensions: MOI flags = 0x21 label explicit-null
nexthop YYY.YYY.230.102 GigabitEthernet0/0/23 label [explicit-null|explicit-null], IP adj out of GigabitEthernet0/0/23, addr YYY.YYY.230.102 3C287540
repair: attached-nexthop XXX.XXX.67.152 GigabitEthernet0/0/22 (3D4A44A4)
path 3D4A44A4, share 1/1, type attached nexthop, for IPv4, flags [has-rpr]
MPLS short path extensions: MOI flags = 0x21 label explicit-null
nexthop XXX.XXX.67.152 GigabitEthernet0/0/22 label [explicit-null|explicit-null], IP adj out of GigabitEthernet0/0/22, addr XXX.XXX.67.152 3CC74980
repair: attached-nexthop YYY.YYY.230.102 GigabitEthernet0/0/23 (3D4A221C)
output chain:
loadinfo 3D43D410, per-session, 2 choices, flags 0103, 21 locks
flags [Per-session, for-rx-IPv4, indirection]
16 hash buckets
< 0 > label [explicit-null|explicit-null]
FRR Primary (0x3D51B980)
<primary: TAG adj out of GigabitEthernet0/0/22, addr XXX.XXX.67.152 3D643CE0>
<repair: TAG adj out of GigabitEthernet0/0/23, addr YYY.YYY.230.102 3CC74300>
< 1 > label [explicit-null|explicit-null]
FRR Primary (0x3D51BA40)
<primary: TAG adj out of GigabitEthernet0/0/23, addr YYY.YYY.230.102 3CC74300>
<repair: TAG adj out of GigabitEthernet0/0/22, addr XXX.XXX.67.152 3D643CE0>
< 2 > label [explicit-null|explicit-null]
FRR Primary (0x3D51B980)
<primary: TAG adj out of GigabitEthernet0/0/22, addr XXX.XXX.67.152 3D643CE0>
<repair: TAG adj out of GigabitEthernet0/0/23, addr YYY.YYY.230.102 3CC74300>
< 3 > label [explicit-null|explicit-null]
FRR Primary (0x3D51BA40)
<primary: TAG adj out of GigabitEthernet0/0/23, addr YYY.YYY.230.102 3CC74300>
<repair: TAG adj out of GigabitEthernet0/0/22, addr XXX.XXX.67.152 3D643CE0>
< 4 > label [explicit-null|explicit-null]
FRR Primary (0x3D51B980)
<primary: TAG adj out of GigabitEthernet0/0/22, addr XXX.XXX.67.152 3D643CE0>
<repair: TAG adj out of GigabitEthernet0/0/23, addr YYY.YYY.230.102 3CC74300>
< 5 > label [explicit-null|explicit-null]
FRR Primary (0x3D51BA40)
<primary: TAG adj out of GigabitEthernet0/0/23, addr YYY.YYY.230.102 3CC74300>
<repair: TAG adj out of GigabitEthernet0/0/22, addr XXX.XXX.67.152 3D643CE0>
< 6 > label [explicit-null|explicit-null]
FRR Primary (0x3D51B980)
<primary: TAG adj out of GigabitEthernet0/0/22, addr XXX.XXX.67.152 3D643CE0>
<repair: TAG adj out of GigabitEthernet0/0/23, addr YYY.YYY.230.102 3CC74300>
< 7 > label [explicit-null|explicit-null]
FRR Primary (0x3D51BA40)
<primary: TAG adj out of GigabitEthernet0/0/23, addr YYY.YYY.230.102 3CC74300>
<repair: TAG adj out of GigabitEthernet0/0/22, addr XXX.XXX.67.152 3D643CE0>
< 8 > label [explicit-null|explicit-null]
FRR Primary (0x3D51B980)
<primary: TAG adj out of GigabitEthernet0/0/22, addr XXX.XXX.67.152 3D643CE0>
<repair: TAG adj out of GigabitEthernet0/0/23, addr YYY.YYY.230.102 3CC74300>
< 9 > label [explicit-null|explicit-null]
FRR Primary (0x3D51BA40)
<primary: TAG adj out of GigabitEthernet0/0/23, addr YYY.YYY.230.102 3CC74300>
<repair: TAG adj out of GigabitEthernet0/0/22, addr XXX.XXX.67.152 3D643CE0>
<10 > label [explicit-null|explicit-null]
FRR Primary (0x3D51B980)
<primary: TAG adj out of GigabitEthernet0/0/22, addr XXX.XXX.67.152 3D643CE0>
<repair: TAG adj out of GigabitEthernet0/0/23, addr YYY.YYY.230.102 3CC74300>
<11 > label [explicit-null|explicit-null]
FRR Primary (0x3D51BA40)
<primary: TAG adj out of GigabitEthernet0/0/23, addr YYY.YYY.230.102 3CC74300>
<repair: TAG adj out of GigabitEthernet0/0/22, addr XXX.XXX.67.152 3D643CE0>
<12 > label [explicit-null|explicit-null]
FRR Primary (0x3D51B980)
<primary: TAG adj out of GigabitEthernet0/0/22, addr XXX.XXX.67.152 3D643CE0>
<repair: TAG adj out of GigabitEthernet0/0/23, addr YYY.YYY.230.102 3CC74300>
<13 > label [explicit-null|explicit-null]
FRR Primary (0x3D51BA40)
<primary: TAG adj out of GigabitEthernet0/0/23, addr YYY.YYY.230.102 3CC74300>
<repair: TAG adj out of GigabitEthernet0/0/22, addr XXX.XXX.67.152 3D643CE0>
<14 > label [explicit-null|explicit-null]
FRR Primary (0x3D51B980)
<primary: TAG adj out of GigabitEthernet0/0/22, addr XXX.XXX.67.152 3D643CE0>
<repair: TAG adj out of GigabitEthernet0/0/23, addr YYY.YYY.230.102 3CC74300>
<15 > label [explicit-null|explicit-null]
FRR Primary (0x3D51BA40)
<primary: TAG adj out of GigabitEthernet0/0/23, addr YYY.YYY.230.102 3CC74300>
<repair: TAG adj out of GigabitEthernet0/0/22, addr XXX.XXX.67.152 3D643CE0>
Subblocks:
None
So, all looks ok from a load sharing perspective, but majority of traffic still goes via gi0/0/22......so was wondering if a L3 Etherchannel may provide some "better" balance as it has more algorithm balancing options to choose from? (Or potentially setting up TE, but I think this may be overkill, and not provide more benefit?)
Cheers
________________________________
From: Aaron Gould <aaron1 at gvtc.com>
Sent: Thursday, 31 August 2017 5:19 AM
To: 'CiscoNSP List'; cisco-nsp at puck.nether.net
Subject: RE: [c-nsp] OSPF equal cost load balancing
Are you doing a 2-port etherchannel between the 920 and 3600 ? Asking since you seem to be asking question about etherchannel load balancing and hashing
...or...
Are you doing 2 separate layer 3 subnets between the 920 and 3600 ? asking since your subject heading implies so. (ospf equal cost LB)
...you might be confusing/mixing 2 different subjects and how-to's in the same explanation.
I think you mentioned the 920 is network side and 3600 is closer to customer... if so, please go to 920 and show a customer route on the 3600 that you wish you would load balance please... sanitize your output to protect the innocent...
Show ip route a.b.c.d
Show ip arp of next hop
If it goes via L2....
Show mac-address-table address aaaa.bbbb.cccc
-Aaron
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