# US 10,122,624 B2 · System and method for ephemeral entries in a forwarding information base in a content centric network

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- Number: US 10,122,624 B2
- Document ID: US10122624B2
- Status: Granted
- Kind: B2
- Application number: 15/218,733
- Filed: 2016-07-25
- Published: 2018-01-25
- Granted: 2018-11-06
- Earliest claimed: 2016-07-25
- Assignees: Cisco Technology, Inc.
- Applicants: Cisco Technology, Inc.
- Inventors: Christopher A. Wood; Glenn C. Scott
- Web page: https://patentgrep.com/patent/US10122624B2

## CPC

- H04L 45/54: {Organization of routing tables}
- H04L 45/021: Ensuring consistency of routing table updates, e.g. by using epoch numbers
- H04L 45/028: Dynamic adaptation of the update intervals, e.g. event-triggered updates
- H04L 45/566: {Routing instructions carried by the data packet, e.g. active networks}
- H04L 45/742: {Route cache; Operation thereof}
- H04L 61/45: Network directories; Name-to-address mapping
- H04L 67/63: Routing a service request depending on the request content or context
- H04L 69/28: Timers or timing mechanisms used in protocols
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

One embodiment provides a system that facilitates efficient management of a forwarding information base (FIB). During operation, the system receives, by an intermediate node, a first interest which includes a name and a condition for removing a first entry from a FIB, wherein a name is a hierarchically structured variable length identifier that includes contiguous name components ordered from a most general level to a most specific level. In response to obtaining the first entry from the FIB based on the name for the first interest, the system adds to the first entry the condition included in the first interest as a lifetime value for the first entry. In response to determining that the lifetime value is satisfied, the system removes the first entry from the FIB, thereby facilitating the intermediate node to efficiently manage the FIB based on information provided by a content producing device.

## Claims

### Claim 1

A computer system for facilitating ephemeral entries in a forwarding information base, the system comprising:
a processor; and
a storage device storing instructions that when executed by the processor cause the processor to perform:
receiving, by an intermediate node, a first interest which includes a name and a condition for removing a first entry from a forwarding information base, wherein a name is a hierarchically structured variable length identifier that includes contiguous name components ordered from a most general level to a most specific level;
in response to obtaining the first entry from the forwarding information base based on the name for the first interest, adding to the first entry the condition included in the first interest as a lifetime value for the first entry; and
in response to determining that the lifetime value is satisfied, removing the first entry from the forwarding information base,
thereby facilitating the intermediate node to efficiently manage the forwarding information base based on information provided by a content producing device.

### Claim 2 (depends on 1)

The computer system of claim 1, wherein the condition indicates an absolute clock value, and wherein determining that the lifetime value is satisfied comprises:
detecting an expiration of the absolute clock value.

### Claim 3 (depends on 1)

The computer system of claim 1, wherein the condition indicates a stale clock value, and wherein determining that the lifetime value is satisfied comprises:
detecting that no subsequent interests are forwarded based on the first entry before an expiration of the stale clock value; and
in response to forwarding a subsequent interest based on the first entry before the expiration of the stale clock value, resetting the lifetime value for the first entry based on the stale clock value.

### Claim 4 (depends on 3)

The computer system of claim 3, wherein the condition further indicates an interest threshold, which indicates a number of forwarded interests after which the lifetime value is to be reset, and wherein determining that the lifetime value is satisfied comprises:
detecting that a number of interests less than the interest threshold is forwarded based on the first entry before the expiration of the stale clock value; and
in response to forwarding a number of subsequent interests equal to the interest threshold based on the first entry before the expiration of the stale clock value, resetting the lifetime value for the first entry based on the stale clock value.

### Claim 5 (depends on 4)

The computer system of claim 4, wherein the condition indicates one or more of an absolute clock value, the stale clock value, the interest threshold, and a reference count which is an integer indicating a number of interests that can be forwarded based on the first entry before the first entry is to be removed from the forwarding information base, and wherein determining that the lifetime value is satisfied further comprises one or more of:
detecting an expiration of the absolute clock value; and
in response to forwarding an interest based on the first entry:
decrementing by one the reference count indicated in the lifetime value for the first entry; and
determining that the reference count is zero.

### Claim 6 (depends on 1)

The computer system of claim 1, wherein the condition further indicates a reference count, which is an integer indicating a number of interests that can be forwarded based on the first entry before the first entry is to be removed from the forwarding information base, and wherein determining that the lifetime value is satisfied comprises:
in response to forwarding the first interest or a second interest to an outgoing interface indicated in the first entry:
decrementing by one the reference count indicated in the lifetime value for the first entry; and
determining that the reference count is zero.

### Claim 7 (depends on 1)

The computer system of claim 1, wherein the first interest is an advertisement of the content producing device for content under a domain of the content producing device, and wherein the advertisement does not require a responsive content object and does not leave state information in a pending interest table.

### Claim 8

A computer-implemented method for facilitating ephemeral entries in a forwarding information base, the method comprising:
receiving, by an intermediate node, a first interest which includes a name and a condition for removing a first entry from a forwarding information base, wherein a name is a hierarchically structured variable length identifier that includes contiguous name components ordered from a most general level to a most specific level;
in response to obtaining the first entry from the forwarding information base based on the name for the first interest, adding to the first entry the condition included in the first interest as a lifetime value for the first entry; and
in response to determining that the lifetime value is satisfied, removing the first entry from the forwarding information base,
thereby facilitating the intermediate node to efficiently manage the forwarding information base based on information provided by a content producing device.

### Claim 9 (depends on 8)

The method of claim 8, wherein the condition indicates an absolute clock value, and wherein determining that the lifetime value is satisfied comprises:
detecting an expiration of the absolute clock value.

### Claim 10 (depends on 8)

The method of claim 8, wherein the condition indicates a stale clock value, and wherein determining that the lifetime value is satisfied comprises:
detecting that no subsequent interests are forwarded based on the first entry before an expiration of the stale clock value; and
in response to forwarding a subsequent interest based on the first entry before the expiration of the stale clock value, resetting the lifetime value for the first entry based on the stale clock value.

### Claim 11 (depends on 10)

The method of claim 10, wherein the condition further indicates an interest threshold, which indicates a number of forwarded interests after which the lifetime value is to be reset, and wherein determining that the lifetime value is satisfied comprises:
detecting that a number of interests less than the interest threshold is forwarded based on the first entry before the expiration of the stale clock value; and
in response to forwarding a number of subsequent interests equal to the interest threshold based on the first entry before the expiration of the stale clock value, resetting the lifetime value for the first entry based on the stale clock value.

### Claim 12 (depends on 11)

The method of claim 11, wherein the condition indicates one or more of an absolute clock value, the stale clock value, the interest threshold, and a reference count which is an integer indicating a number of interests that can be forwarded based on the first entry before the first entry is to be removed from the forwarding information base, and wherein determining that the lifetime value is satisfied further comprises one or more of:
detecting an expiration of the absolute clock value; and
in response to forwarding an interest based on the first entry:
decrementing by one the reference count indicated in the lifetime value for the first entry; and
determining that the reference count is zero.

### Claim 13 (depends on 8)

The method of claim 8, wherein the condition further indicates a reference count, which is an integer indicating a number of interests that can be forwarded based on the first entry before the first entry is to be removed from the forwarding information base, and wherein determining that the lifetime value is satisfied comprises:
in response to forwarding the first interest or a second interest to an outgoing interface indicated in the first entry:
decrementing by one the reference count indicated in the lifetime value for the first entry; and
determining that the reference count is zero.

### Claim 14 (depends on 8)

The method of claim 8, wherein the first interest is an advertisement of the content producing device for content under a domain of the content producing device, and wherein the advertisement does not require a responsive content object and does not leave state information in a pending interest table.

### Claim 15

A non-transitory computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method, the method comprising:
receiving, by an intermediate node, a first interest which includes a name and a condition for removing a first entry from a forwarding information base, wherein a name is a hierarchically structured variable length identifier that includes contiguous name components ordered from a most general level to a most specific level;
in response to obtaining the first entry from the forwarding information base based on the name for the first interest, adding to the first entry the condition included in the first interest as a lifetime value for the first entry; and
in response to determining that the lifetime value is satisfied, removing the first entry from the forwarding information base,
thereby facilitating the intermediate node to efficiently manage the forwarding information base based on information provided by a content producing device.

### Claim 16 (depends on 15)

The storage medium of claim 15, wherein the condition indicates an absolute clock value, and wherein determining that the lifetime value is satisfied comprises:
detecting an expiration of the absolute clock value.

### Claim 17 (depends on 15)

The storage medium of claim 15, wherein the condition indicates a stale clock value, and wherein determining that the lifetime value is satisfied comprises:
detecting that no subsequent interests are forwarded based on the first entry before an expiration of the stale clock value; and
in response to forwarding a subsequent interest based on the first entry before the expiration of the stale clock value, resetting the lifetime value for the first entry based on the stale clock value.

### Claim 18 (depends on 17)

The storage medium of claim 17, wherein the condition further indicates an interest threshold, which indicates a number of forwarded interests after which the lifetime value is to be reset, and wherein determining that the lifetime value is satisfied comprises:
detecting that a number of interests less than the interest threshold is forwarded based on the first entry before the expiration of the stale clock value; and
in response to forwarding a number of subsequent interests equal to the interest threshold based on the first entry before the expiration of the stale clock value, resetting the lifetime value for the first entry based on the stale clock value.

### Claim 19 (depends on 18)

The storage medium of claim 18, wherein the condition indicates one or more of an absolute clock value, the stale clock value, the interest threshold, and a reference count which is an integer indicating a number of interests that can be forwarded based on the first entry before the first entry is to be removed from the forwarding information base, and wherein determining that the lifetime value is satisfied further comprises one or more of:
detecting an expiration of the absolute clock value; and
in response to forwarding an interest based on the first entry:
decrementing by one the reference count indicated in the lifetime value for the first entry; and
determining that the reference count is zero.

### Claim 20 (depends on 15)

The storage medium of claim 15, wherein the condition further indicates a reference count, which is an integer indicating a number of interests that can be forwarded based on the first entry before the first entry is to be removed from the forwarding information base, and wherein determining that the lifetime value is satisfied comprises:
in response to forwarding the first interest or a second interest to an outgoing interface indicated in the first entry:
decrementing by one the reference count indicated in the lifetime value for the first entry; and
determining that the reference count is zero.