US-12627601-B2 - Physical layer metadata carrier for ethernet systems

US12627601B2US 12627601 B2US12627601 B2US 12627601B2US-12627601-B2

Abstract

Techniques for, among other things, embedding metadata in network traffic without having to implement an overlay network. By way of example, and not limitation, the techniques described herein may include receiving an Ethernet packet at a network node and determining that a preamble of the Ethernet packet includes metadata. The metadata may, in some examples, be associated with the Ethernet packet itself, a flow that the Ethernet packet belongs to, etc. Based at least in part on the metadata, a policy decision may be made for handling the Ethernet packet, and the Ethernet packet may be handled in accordance with the policy decision.

Inventors

David John Zacks
Thomas Szigeti
Barry Qi Yuan
Robert Edgar Barton

Assignees

CISCO TECHNOLOGY, INC.

Dates

Publication Date: 20260512
Application Date: 20230607

Claims (20)

1 . A method performed at least partially by a first network node, the method comprising: receiving an Ethernet packet sent by a second network node via an Ethernet link between the first network node and the second network node; determining that a preamble of the Ethernet packet includes metadata by: determining that a first portion of the preamble includes a bit pattern indicating that a second portion of the preamble includes the metadata; determining, based at least in part on the metadata, a policy decision associated with handling the Ethernet packet; and handling the Ethernet packet based at least in part on the policy decision.
2 . The method of claim 1 , wherein the first portion of the preamble and the second portion of the preamble precede a third portion of the preamble, the third portion of the preamble including a synchronization bit pattern.
3 . The method of claim 1 , further comprising refraining from discarding the preamble of the Ethernet packet based at least in part on determining that the preamble includes the metadata.
4 . The method of claim 1 , wherein the bit pattern is a first bit pattern, the method further comprising determining, based at least in part on a second bit pattern included in the preamble, a first process within the first network node for handling the Ethernet packet.
5 . The method of claim 4 , wherein the second bit pattern is distinguishable from a third bit pattern, the third bit pattern indicative of a second process within the first network node for handling Ethernet packets, the second process distinguishable from the first process.
6 . The method of claim 1 , further comprising: determining that the metadata is to be provided to a third network node; storing, in a cache memory, the metadata while the Ethernet packet internally transits the first network node; and embedding the metadata in the preamble of another Ethernet packet prior to sending the other Ethernet packet to the third network node.
7 . The method of claim 1 , wherein the metadata is associated with at least one of the Ethernet packet itself or a flow that the Ethernet packet belongs to.
8 . A system associated with a first network node, the system comprising: one or more processors; and one or more non-transitory computer-readable media storing instructions that, when executed, cause the one or more processors to perform operations comprising: receiving an Ethernet packet sent by a second network node via an Ethernet link between the first network node and the second network node; determining that a preamble of the Ethernet packet includes metadata by: determining that a first portion of the preamble includes a bit pattern indicating that a second portion of the preamble includes the metadata; determining, based at least in part on the metadata, a policy decision associated with handling the Ethernet packet; and handling the Ethernet packet based at least in part on the policy decision.
9 . The system of claim 8 , wherein the first portion of the preamble and the second portion of the preamble precede a third portion of the preamble, the third portion of the preamble including a synchronization bit pattern.
10 . The system of claim 8 , the operations further comprising refraining from discarding the preamble of the Ethernet packet based at least in part on determining that the preamble includes the metadata.
11 . The system of claim 8 , wherein the bit pattern is a first bit pattern, the operations further comprising determining, based at least in part on a second bit pattern included in the preamble, a first process within the first network node for handling the Ethernet packet.
12 . The system of claim 11 , wherein the second bit pattern is distinguishable from a third bit pattern, the third bit pattern indicative of a second process within the first network node for handling Ethernet packets, the second process distinguishable from the first process.
13 . The system of claim 8 , the operations further comprising: determining that the metadata is to be provided to a third network node; storing, in a cache memory, the metadata while the Ethernet packet internally transits the first network node; and embedding the metadata in the preamble of another Ethernet packet prior to sending the other Ethernet packet to the third network node.
14 . The system of claim 8 , wherein the metadata is associated with at least one of the Ethernet packet itself or a flow that the Ethernet packet belongs to.
15 . A network node including a physical layer (PHY) transceiver that is configured to perform operations comprising: receiving an Ethernet packet sent by another network node via an Ethernet link between the network node and the other network node; determining, based at least in part on a bit pattern included in a first portion of a preamble of the Ethernet packet, that a second portion of the preamble includes metadata; and based at least in part on the metadata, causing the Ethernet packet to be processed within the network node using a first processing algorithm that is distinguishable from a second processing algorithm.
16 . The network node of claim 15 , wherein the first portion of the preamble and the second portion of the preamble precede a third portion of the preamble, the third portion of the preamble including a synchronization bit pattern.
17 . The network node of claim 15 , wherein the metadata is associated with at least one of the Ethernet packet itself or a flow the Ethernet packet belongs to.
18 . The network node of claim 15 , the operations further comprising refraining from discarding the preamble of the Ethernet packet based at least in part on the preamble including the metadata.
19 . The method of claim 1 , further comprising: determining, based on the first portion of the preamble, a type of the metadata included in the second portion of the preamble.
20 . The system of claim 8 , wherein a length of the bit pattern is 4-bits, 5-bits, 6-bits, 7-bits, or 1-byte.

Description

TECHNICAL FIELD The present disclosure relates generally to techniques for, among other things, embedding metadata in network traffic without having to implement an overlay network. BACKGROUND A standard Internet Protocol version 4 (IPv4) packet lacks any place within the header to embed metadata concerning the packet itself or the end-to-end flow that the packet is part of. For instance, simple extension headers can be utilized in Internet Protocol version 6 (IPv6) to carry such metadata, but these technologies are not available for IPV4. Instead, passing metadata information in IPv4 from node to node within a network along a flow path requires the use of an overlay network, using technologies such as Virtual Extensible LAN (VXLAN), Multiprotocol Label Switching (MPLS), Virtual Private Networking (VPN), or similar technologies that allow for an extension of the IP packet header, thus providing a location where such metadata can be embedded. While functional, the implementation of such technologies on a large scale can oftentimes be impractical. Unfortunately, in some scenarios, lacking metadata restricts a node's ability to handle traffic in more sophisticated ways. BRIEF DESCRIPTION OF THE DRAWINGS The detailed description is set forth below with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The use of the same reference numbers in different figures indicates similar or identical items. The systems depicted in the accompanying figures are not to scale and components within the figures may be depicted not to scale with each other. FIG. 1 illustrates a portion of an example architecture in which various aspects of the techniques disclosed herein may be performed to embed metadata within an Ethernet packet. FIG. 2A is a block diagram illustrating example detail of a portion of an Ethernet packet that is modified to carry metadata according to the technologies disclosed herein. FIG. 2B illustrates a comparison between a traditional, layer-1 Ethernet packet and a modified layer-1 Ethernet packet for carrying metadata according to the technologies disclosed herein. FIG. 3 is a flow diagram illustrating an example method associated with the techniques described herein. FIG. 4 is a flow diagram illustrating an example method associated with the techniques described herein. FIG. 5 is a block diagram illustrating an example packet switching system that can be utilized to implement various aspects of the technologies disclosed herein. FIG. 6 is a block diagram illustrating certain components of an example node that can be utilized to implement various aspects of the technologies disclosed herein. FIG. 7 is a computer architecture diagram showing an illustrative computer hardware architecture for implementing a computing device that can be utilized to implement aspects of the various technologies presented herein. DESCRIPTION OF EXAMPLE EMBODIMENTS Overview This disclosure describes various technologies for, among other things, embedding metadata in network traffic without having to implement an overlay network. By way of example, and not limitation, the techniques described herein may include receiving an Ethernet packet at a network node and determining that a preamble of the Ethernet packet includes metadata. Based at least in part on the metadata, a policy decision may be made for handling the Ethernet packet and the Ethernet packet may be handled in accordance with the policy decision. Additionally, the techniques described herein may be performed as a method and/or by a system having non-transitory computer-readable media storing computer-executable instructions that, when executed by one or more processors, performs the techniques described above and herein. EXAMPLE EMBODIMENTS As noted above, standard IPv4 packets lack any place within the headers to embed metadata concerning the packet itself or the end-to-end flow that the packet is part of. Instead, passing metadata information from node to node within a network along a flow path requires the use of an overlay network, using technologies such as VXLAN. MPLS. VPN, or similar technologies that allow for an extension of the IP packet header, thus providing a location where such metadata can be embedded. While functional, the implementation of such technologies on a large scale can oftentimes be impractical and, in some scenarios, lacking metadata restricts a node's ability to handle traffic in more sophisticated ways. This application is directed to techniques for passing frame metadata between network nodes (e.g., switches, routers, hosts, etc.) in Ethernet systems by utilizing an extension to Ethernet packet formatting to allow metadata exchange. For example, a preamble field of an Ethernet packet may be utilized to carry telemetry data. In some examples, a bit pattern may be embedded in a first portion of the preamble to indicate that a