Cisco Cisco Dynamic Fabric Automation for OpenStack 문제 해결 가이드
Cisco Dynamic Fabric Automation Production Troubleshooting Guide
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BGP routing table information for VRF seinfeld:vandelay, address family IPv4 Uni
cast
BGP table version is 453322, local router ID is 20.10.100.1
Status: s-suppressed, x-deleted, S-stale, d-dampened, h-history, *-valid, >-best
Path type: i-internal, e-external, c-confed, l-local, a-aggregate, r-redist, I-i
njected
Origin codes: i - IGP, e - EGP, ? - incomplete, | - multipath, & - backup
Network Next Hop Metric LocPrf Weight Path
* i20.10.100.0/24 10.1.10.122 0 100 0 ?
* i 10.1.10.121 0 100 0 ?
* i 10.1.10.124 0 100 0 ?
*>r 0.0.0.0 0 100 32768 ?
*>r20.10.100.11/32 0.0.0.0 0 100 32768 ?
*>r20.10.100.70/32 0.0.0.0 0 100 32768 ?
*>i20.10.100.71/32 10.1.10.121 0 100 0 ?
3.3.2 HMM Handing a Host Move Event
Host movement across a DFA fabric can be detected by Layer-2, non-IP traffic or IP ARP traffic independently. Some
hosts may generate Layer-2 non-IP traffic and IP traffic while other hosts only generate one or the other at a given
period of time.
hosts may generate Layer-2 non-IP traffic and IP traffic while other hosts only generate one or the other at a given
period of time.
Host movement events are tracked by two separate but related processes, MAC move notification and Adjacency
move notification. If Fabricpath learns the MAC remotely, but there is no ARP/Adjacency update, HMM will then update
the old DFA leaf switch with the new MAC location via a notification from the Layer 2 Feature Manager (L2FM) pro-
cess. If IP traffic is routed across the fabric using an existing /32 route, then it is forwarded to the old DFA leaf. As a
result, the DFA leaf will switch traffic via Layer-2 FabricPath back across the fabric to the new host location that adver-
tised the move via L2FM, but the updated MAC table learns the FabricPath Switch ID. This sub-optimal hair pinning of
traffic across the DFA fabric will be resolved or avoided by prompt receipt of an ARP frame from the new DFA leaf.
move notification. If Fabricpath learns the MAC remotely, but there is no ARP/Adjacency update, HMM will then update
the old DFA leaf switch with the new MAC location via a notification from the Layer 2 Feature Manager (L2FM) pro-
cess. If IP traffic is routed across the fabric using an existing /32 route, then it is forwarded to the old DFA leaf. As a
result, the DFA leaf will switch traffic via Layer-2 FabricPath back across the fabric to the new host location that adver-
tised the move via L2FM, but the updated MAC table learns the FabricPath Switch ID. This sub-optimal hair pinning of
traffic across the DFA fabric will be resolved or avoided by prompt receipt of an ARP frame from the new DFA leaf.
When the new DFA leaf switch snoops an ARP packet from the moved host, a new HMM host entry is created. This
new route will be re-distributed across the DFA fabric and trigger a flush of the host entry on the old leaf, where HMM
previously learned the host location. Subsequently, all routed traffic to this host IP will be forwarded directly to the new
DFA leaf next-hop.
new route will be re-distributed across the DFA fabric and trigger a flush of the host entry on the old leaf, where HMM
previously learned the host location. Subsequently, all routed traffic to this host IP will be forwarded directly to the new
DFA leaf next-hop.
When a locally learned host HMM IP/MAC binding is seen across the fabric on a remote DFA leaf the stale entry must
be flushed from HMM and withdrawn from iBGP to support host mobility. It is important that hosts re-ARP after a move
event for quick propagation of the correct route entry across the DFA fabric.
be flushed from HMM and withdrawn from iBGP to support host mobility. It is important that hosts re-ARP after a move
event for quick propagation of the correct route entry across the DFA fabric.
Initially we can see that host 20.10.100.11 is locally learned by HMM on port-channel 10.
dfa-n6k-leaf-1# show fabric forwarding ip local-host-db vrf seinfeld:vandelay 20.10.100.11/32
HMM routing table information for VRF seinfeld:vandelay, address family IPv4
HMM routing table entry for 20.10.100.11/32
Hosts: (1 available)
Host type: Local(Flags: 0x20201), in Rib
mac: 0000.0000.000a, svi: Vlan100, bd: 100, phy_intf: port-channel10