BACKGROUND

Embodiments of the invention relate to GRE DNS resolution and tunnel creation in network device having eRouter and eCM.

IP serves as the base for a number of different protocols; by far the most common are TCP, UDP, and ICMP. IP over IP (i.e., an IP packet encapsulated within another IP packet) may be used for tunneling protocols over ordinary IP networks. TCP is the protocol most commonly used for services on the Internet. For example, Telnet, FTP, SMTP, NNTP, and HTTP are all TCP-based services. TCP provides a reliable, bidirectional connection between two endpoints.

Tunnels provide a way to transport protocols that the underlying network does not support. For example, a network infrastructure may not support a particular protocol being used, the network infrastructure may not be able to route the packets due to a lack of routing information or addressing types (public addressing vs. private addressing), and the network infrastructure may not support the traffic type (multicast or broadcast). Generic Routing Encapsulation (GRE) is a tunneling protocol that encapsulates network layer protocols inside virtual point-to-point links over an Internet Protocol (IP) network. The two endpoints are identified by the tunnel source and tunnel destination addresses at each endpoint.

Some network devices include both an embedded cable modem (eCM) and an embedded router (eRouter). The cable modem bridges frames between a client LAN and an operator's WAN network. The eRouter uses a DHCP server to provide the LAN with IP network addressing. At initiation, a configuration file is downloaded to the network device. An application programming interface implements a physical interface at the eRouter for configuring the GRE tunnel. However, the eCM may have a separate subnet with a different IP address range than the eRouter side. The user may want to configure a GRE tunnel on the eCM side. For example, the eRouter may be configured with an IPv4 IP address range, whereas the eCM may be configured with an IPv6 address range. Thus, a physical interface on the eCM side would be advantageous so that a GRE tunnel may be configured on the eCM side for the range of addresses that may be configured on the eCM side.

SUMMARY

Aspects of the present invention are directed to a network device having an embedded router (eRouter) and an embedded cable modem (eCM). an API supports selection of the nameserver, selection of the sending interface, and selection of different querying types. The API provisions an eRouter physical interface and an eCM physical interface that allows selection of transmission of the DNS request either from the eRouter side or from the eCM side.

