Tenant dhcp in an overlay network

Abstract

Systems, methods, and non-transitory computer-readable storage media for dynamic host configuration protocol (DHCP) relay functionality in overlay networks. A system on a overlay network fabric can first receive a DHCP request from a host device, the system including a tunnel endpoint (TEP) configured to connect the host device to the overlay network fabric via a tunnel. The system then enables a relay agent information option for relaying the DHCP request with sub-options inserted into the DHCP request, and inserts information into to the sub-options in the DHCP request to yield a modified DHCP request. Here, the information can include an address of the system and an interface of a circuit associated with the system, etc. Next, the system forwards the modified DHCP request to a destination DHCP server based on an address of the destination DHCP server associated with the DHCP request.

1 . A method comprising:
 receiving, via a receiving switch on an overlay fabric network, a dynamic host configuration protocol (DHCP) request from a host device, the receiving switch comprising a tunnel endpoint (TEP) configured to connect the host device to the overlay fabric network via a tunnel;   enabling a relay agent information option for relaying the DHCP request with sub-option fields on the DHCP request, the sub-option fields for inserting information into the DHCP request;   inserting information into to at least one of the sub-option fields in the DHCP request to yield a modified DHCP request, the information comprising at least one of an address of the receiving switch and an interface of a circuit associated with the receiving switch; and   forwarding the modified DHCP request to a destination DHCP server based on an address of the destination DHCP server associated with the DHCP request.   
     
     
         2 . The method of  claim 1 , wherein the information is inserted into a sub-option field in the DHCP request based on the relay agent information option, wherein the sub-option field comprises a remote identifier, the address of the receiving switch comprising at least one of a TEP IP address, a receiving switch media access control (MAC) address, and an overlay virtual routing and forwarding (VRF) IP address, and the relay agent information option being option 82. 
     
     
         3 . The method of  claim 1 , wherein the receiving switch comprises at least one of a top-of-rack switch, a leaf switch, a virtual switch, an edge device in the overlay network fabric, a virtual tunnel endpoint (VTEP), an ingress switch in the overlay network fabric, and a port in a pervasive switch virtual interface. 
     
     
         4 . The method of  claim 1 , wherein the information further comprises at least one of a circuit identifier, a server identifier override, a link identifier selection, a gateway interface address, and a virtual network identifier. 
     
     
         5 . The method of  claim 4 , wherein the circuit identifier comprises at least one of an interface index value associated with an ingress interface and an endpoint group (EPG) virtual network identifier (VNID) associated with the ingress interface. 
     
     
         6 . The method of  claim 4 , wherein the server identifier override comprises a pervasive switch virtual interface (SVI) IP address of a bridge domain associated with the receiving switch. 
     
     
         7 . The method of  claim 6 , wherein the link identifier selection comprises a subnet of the pervasive SVI IP address. 
     
     
         8 . The method of  claim 4 , wherein the gateway interface address (GIADDR) comprises one of an IP address associated with an interface facing the destination DHCP server or a pervasive IP address associated with a bridge domain in a virtual routing and forwarding (VRF) instance. 
     
     
         9 . The method of  claim 4 , wherein the virtual network identifier (VNID) comprises a virtual routing and forwarding (VRF) name. 
     
     
         10 . The method of  claim 1 , wherein virtual machines reside in the overlay network fabric and communicate with the overlay network fabric via a tunnel provided by the receiving switch. 
     
     
         11 . The method of  claim 1 , wherein the overlay network fabric comprises at least one of a virtual extensible local area network (VXLAN), Network Virtualization using Generic Routing Encapsulation (NVGRE) network, a Stateless transport tunneling (STT) network, a spine-leaf network, and a CLOS network, the method further comprising:
 receiving a response to the DHCP request from the DHCP server, the response comprising a DHCP lease offer; and   relaying the response to the host device.   
     
     
         12 . A system comprising:
 a processor; and   a computer-readable storage medium having stored therein instructions which, when executed by the processor, cause the processor to perform operations comprising:
 receiving, via a receiving switch on an overlay network, a dynamic host configuration protocol (DHCP) request from a device, the receiving switch comprising a tunnel endpoint (TEP) configured to connect the device to the overlay network via a tunnel; 
 enabling a relay agent information option for DHCP requests on the receiving switch, the relay agent information option providing sub-option fields for inserting information into the DHCP request for relaying additional information into the DHCP request; 
 inserting information into to the sub-options in the DHCP request to yield a modified DHCP request, the information comprising at least one of an address of the receiving switch and interface information associated with a circuit where the receiving switch resides; and 
 relaying the modified DHCP request to a destination DHCP server based on an address of the destination DHCP server associated with the DHCP request. 
   
     
     
         13 . The system of  claim 12 , the computer-readable storage medium storing additional instructions which, when executed by the processor, result in an operation further comprising:
 receiving a response to the DHCP request from the destination DHCP server, the response comprising a DHCP lease offer; and   relaying the response to the device based on routing information contained in at least one of the response and the DHCP request.   
     
     
         14 . The system of  claim 12 , wherein the sub-option fields comprise a first field for indicating a remote identifier, and a second field for indicating the address of the receiving switch comprising an overlay virtual routing and forwarding (VRF) IP address, the relay agent information option being option 82. 
     
     
         15 . The system of  claim 12 , wherein the receiving switch comprises at least one of a top-of-rack switch, a leaf switch, a virtual switch, an edge device in the overlay network fabric, a virtual tunnel endpoint (VTEP), and a port in a pervasive switch virtual interface. 
     
     
         16 . The system of  claim 12 , wherein the information further comprises at least one of a circuit identifier, a server identifier override, a link identifier selection, a gateway interface address, and a virtual private network identifier. 
     
     
         17 . A non-transitory computer-readable storage medium having stored therein instructions which, when executed by a processor, cause the processor to perform operations comprising:
 receiving, via a receiving switch on an overlay network, a dynamic host configuration protocol (DHCP) request from a host, the receiving switch comprising a tunnel endpoint (TEP) configured to connect the host to the overlay network via a tunnel;   enabling a relay agent information option for DHCP requests on the receiving switch, the relay agent information option providing sub-option fields for inserting information into the DHCP request for inserting additional information into the DHCP request prior to forwarding the DHCP request;   inserting information into to at least one of the sub-options in the DHCP request to yield a modified DHCP request, the information comprising at least one of an address of the receiving switch and an interface of a circuit associated with the receiving switch; and   forwarding the modified DHCP request to a destination DHCP server based on an address of the destination DHCP server associated with the DHCP request.   
     
     
         18 . The non-transitory computer-readable storage medium of  claim 17 , storing additional instructions which, when executed by the processor, result in operations further comprising:
 receiving a response to the DHCP request from the destination DHCP server; and   forwarding the response to the device based on routing information contained in at least one of the response and the DHCP request.   
     
     
         19 . The non-transitory computer-readable storage medium of  claim 17 , wherein the information is inserted into a sub-option field in the DHCP request based on the relay agent information option, wherein the sub-option field comprises a remote identifier, the address of the receiving switch comprising an overlay virtual routing and forwarding (VRF) IP address, and the relay agent information option being option 82, and wherein the receiving switch comprises at least one of a top-of-rack switch, a leaf switch, a virtual switch, an edge device in the overlay network fabric, a virtual tunnel endpoint (VTEP), and a port in a pervasive switch virtual interface. 
     
     
         20 . The non-transitory computer-readable storage medium of  claim 17 :
 wherein the information further comprises at least one of a circuit identifier, a server identifier override, a link identifier selection, a gateway interface address, and a virtual private network identifier;   wherein the circuit identifier comprises at least one of an interface index value associated with an ingress interface and an endpoint group (EPG) virtual network identifier (VNID) associated with the ingress interface;   wherein the server identifier override comprises a pervasive switch virtual interface (SVI) IP address of a broadcast domain associated with the receiving switch;   wherein the link identifier selection comprises a subnet of the pervasive SVI IP address;   wherein the gateway interface address (GIADDR) comprises one of an interface IP of an interface facing the destination DHCP server or a pervasive IP address associated with a bridge domain in a virtual routing and forwarding (VRF) instance; and   wherein the virtual network identifier (VNID) comprises a virtual routing and forwarding (VRF) name.