Gateway Router Pending ARP Table for Targeted Reply Propagation
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Solution Overview
Problem
In datacenter networks, the inefficient propagation of Address Resolution Protocol (ARP) packets across interconnected data centers leads to significant unnecessary data traffic and wastage of network resources, as all routers and hosts receive address resolution reply messages, causing unnecessary generation of address resolution table entries for every host in the data centers.
Innovation Solution
Configuring gateway routers to maintain a pending address resolution requests table, where entries include destination IP addresses, source IP and MAC addresses, and a VLAN tag, allowing for targeted transmission of ARP reply messages only to the relevant data center, reducing unnecessary broadcasts and improving resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ARP reply messages are broadcast to all routers and hosts across interconnected data centers, then complete address resolution information is propagated, but unnecessary data traffic and network resource waste increase significantly
Solution Approach 1:
The patent segments the ARP reply propagation by introducing a pending ARP requests table that tracks which data centers have actually requested address resolution. Instead of broadcasting to all data centers uniformly, the system divides the propagation target set based on actual need, sending replies only to data centers with pending requests.
Solution Approach 2:
The gateway router acts as an intermediary between ARP request sources and reply destinations. It maintains a pending ARP requests table that mediates the matching process between incoming ARP replies and outstanding requests, filtering which data centers receive replies based on actual resolution needs.
2Loss of information
If ARP reply messages are sent to all data centers, then all routers can build complete address resolution tables, but CPU and networking resources are wasted on processing unnecessary entries
Solution Approach 1:
The system performs preliminary action by maintaining a pending ARP requests table before ARP replies arrive. This table pre-identifies which data centers have outstanding address resolution requests, allowing the gateway router to filter replies before they are propagated, preventing unnecessary processing at receiving devices.
3Ease of operation
If broadcast ARP replies are used for cross-data center communication, then simple propagation is achieved, but EVPN control plane balance is disrupted
Solution Approach 1:
The system introduces dynamic behavior by having gateway routers maintain and update pending ARP requests tables based on incoming requests and replies. The propagation behavior adapts dynamically to actual resolution needs rather than following a static broadcast pattern, allowing the EVPN control plane to remain balanced by only propagating when necessary.
Data Source
AI summary
Techniques disclosed herein provide a method for efficiently propagating address resolution reply messages. A first router in a first network receives an address resolution request message from a second router in a second network. The first router generates an entry for the address resolution request message and stores the entry in a pending address resolution requests table. When the first router receives a route advertisement, it extracts a network layer address from the route advertisement and determines whether the pending address resolution requests table includes an entry for the network layer address. If so, the router extracts a link layer address from the route advertisement and generates an address resolution reply message comprising the network layer address and the link layer address. The router then transmits the address resolution reply message to the second router.