Administrator Guide

13. When a VM moves from one VLT domain to the another VLT domain, the VM host sends the gratuitous GARP. The GARP triggers a
mac movement from the previous VLT domain to the newer VLT domain.
14. After a station move, if a host sends a TTL1 packet destined to its gateway; for example, a previous VLT node, the packet may be
dropped.
15. After a station move, if a host first PINGs its gateway; for example, a previous VLT node it results a 40 to 60% success rate
considering it takes a longer path.
Enabling the VLT Proxy Gateway
To enable the VLT Proxy Gateway feature, the system mac addresses of C and D in the local VLT domain must be installed in C1 and D1 in
the remote VLT domain and vice versa. You can install the mac address in two methods - the proxy-gateway lldp method or the
proxy-gateway static configuration. Proxy-gateway LLDP is a dynamic method of installing the local mac addresses in the remote
VLT domain, which is achieved using a new organizational TLV in LLDP packets.
The VLT proxy gateway can be configured in a VLT domain context using the cli command proxy-gateway LLDP. You enter the
proxy-gateway Configuration mode when you enter this command. The port-channel interface of the square VLT link on which LLDP
packets are to be sent is specified by thepeer-domain-link port-channel command.
Configuring the proxy gateway lldp and the peer-domain-link port channel, LLDP sets TLV flags on the interfaces for
receiving and transmitting private TLV packets. After defining these organizational TLV settings, LLDP encodes the local system mac-
addresses as organizational TLVs for transmitting to the peer. If you specify the no proxy gateway LLDP interface command,
LLDP stops transmitting and receiving proxy gateway TLV packets on the specified interfaces. However, other TLVs are not affected.
From the interfaces on which proxy gateway LLDP is enabled, LLDP decodes TLV packets from the remote LLDP by using the new
organizational TLV.
The following requirements must be satisfied for LLDP proxy gateway to function correctly:
• Because LLDP is a direct link protocol, data centers must be directly connected.
• LLDP has a limited TLV size. As a result, information that is carried by this new TLV is limited to only one or two MAC addresses.
• You must ensure proper configuration and physical setup on all related systems.
LLDP Organizational TLV for Proxy Gateway
Define a new organizational TLV :
• LLDP defines an organizationally specific TLV (type 127) with an organizationally unique identifier (0x0001E8) and organizationally
defined subtype (0x01) for sending or receiving this information.
• LLDP will uses the existing infrastructure and adds the new TLV, and sends and receives only on the configured ports.
• There are only a couple of MAC addresses for each unit to transmit so all currently active MAC addresses are carried on the newly
defined TLV.
• This TLV is recognizable only by Dell Networking devices with this feature support. Other devices ignore this field and are able to
process other standard TLVs.
The LLDP organizational TLV passes local destination MAC address information to peer VLT domain devices so they can act as the proxy
gateway. Two configurations are required to enable Proxy Gateway LLDP:
• Global proxy gateway LLDP configuration to enable this feature
• Interface proxy gateway LLDP configuration to enable/disable proxy-gateway LLDP TLV on particular interfaces
• The interface is typically a VLT port-channel which connects to a remote VLT domain
• The new proxy gateway TLV is carried on the physical links under the port channel only
• There should be at least one link connection to each unit of the VLT domain
Following are the prerequisites for Proxy Gateway LLDP configuration:
• LLDP must be globally enabled
• No interface– level LLDP disable CLIs on the interfaces configured for proxy gateway, and you must enable both transmission and
reception
• You must connect both units of the remote VLT domain by the port channel member.
• If you connect more than one port to a unit of the remote VLT domain, it must be completed by the time you enable the proxy
gateway LLDP
• You cannot have other conflicting configurations (for example, the no static proxy gateway configuration)
This feature might not operate properly if one of the following conditions is true:
• Any proxy gateway configuration or LLDP configuration is not working
VLT Proxy Gateway
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