Users Guide

● The preceding figure shows a sample square VLT Proxy gateway topology. There are no diagonal links in the square VLT
connection between the C and D in VLT domain 1 and C1 and D1 in the VLT domain 2. This causes sub-optimal routing. For
VLT Proxy Gateway to work in this scenario you must configure the VLT-peer-mac transmit command under VLT
Domain Proxy Gateway LLDP mode, in both C and D (VLT domain 1) and C1 and D1 (VLT domain 2). This behavior is
applicable only in the LLDP configuration and not required in the static configuration.
Sample Configuration
DellEMC(conf-vlt-domain)#proxy-gateway lldp
DellEMC(conf-vlt-domain-pxy-gw-lldp)#vlt-peer-mac transmit
● Assume the inter-chassis link (ICL) between C1 and D1 is shutdown and if D1 is the secondary VLT, one half of the inter DC
link goes down. After VM motion, if a packet reaches D1 with the destination MAC address of D, it may be dropped. This
behavior is applicable only in an LLDP configuration; in a static configuration, the packet is forwarded.
● Any L3 packet, when it gets an L3 hit and is routed, it has a time to live (TTL) decrement as expected.
● You can disable the VLT Proxy Gateway for a particular VLAN using an "Exclude-VLAN" configuration. The configuration has
to be done in both the VLT domains [C and D in VLT domain 1 and C1 and D1 in VLT domain 2].
Sample Configuration LLDP Method
DellEMC(conf-vlt-domain)#proxy-gateway ll
DellEMC(conf-vlt-domain-pxy-gw-lldp)#peer-domain-link port-channel 1 exclude-vlan 10
Sample Configuration Static Method
DellEMC(conf-vlt-domain)#proxy-gateway static
DellEMC(conf-vlt-domain-pxy-gw-static)#remote-mac-address <xx:xx:xx:xx:xx:xx> exclude-
vlan 10
● Packet duplication may happen with “Exclude-VLAN” configuration – Assume you used the exclude-vlan option (called
VLAN 10) in C and D and in C1 and D1; If packets for VLAN 10 with C’s MAC address (C is in VLT domain 1) gets an L3 hit at
C1 in VLT domain 2, they are switched to both D1 (via ICL) and C via inter DC link. This may lead to packet duplication.
Therefore, if C’s MAC address is learned at C1, the packet does not flood to D1 and only switches to C and avoids packet
duplication.
● With the existing hardware capabilities, you can only disable VLT Proxy Gateway only for 500 VLANs, using exclude-VLAN
configuration.
Configuring a Static VLT Proxy Gateway
You can configure a proxy gateway in VLT domains. A proxy gateway allows you to locally route the packets that are destined to
an L3 endpoint of the other VLT domain.
Apply the following configurations in the Core L3 Routers C and D in local VLT domain and C1 and D1 in the remote VLT domain:
1. Configure proxy-gateway static in VLT Domain Configuration mode.
2. Configure remote-mac-address <mac-address> in VLT Domain Proxy Gateway LLDP mode. Configure the system
mac-addresses of both C and D in C1 and also in D1 in the remote VLT domain and vice versa.
Sample Static Configuration on C switch or C1 switch
Switch_C#conf
Switch_C(conf)#vlt domain 1
Switch_C(conf-vlt-domain1)#proxy-gateway static
Switch_C(conf-vlt-domain1-pxy-gw-static)#remote-mac-address <xx:xx:xx:xx:xx:xx>....
Configuring an LLDP VLT Proxy Gateway
You can configure a proxy gateway in a VLT domain to locally route packets destined to a L3 endpoint in another VLT domain.
Apply the following configurations in the Core L3 Routers C and D in the local VLT domain and C1 and D1 in the remote VLT
domain:
1. Configure proxy-gateway lldp in VLT Domain Configuration mode.
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VLT Proxy Gateway