# US 12,538,101 B2 · Multicast rule transformation apparatus and method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,538,101 B2 - Document ID: US12538101B2 - Status: Granted - Kind: B2 - Application number: 18/506,487 - Filed: 2023-11-10 - Published: 2025-04-10 - Granted: 2026-01-27 - Earliest claimed: 2023-10-06 - Assignees: Sysmate Co., Ltd. - Applicants: Sysmate Co., Ltd. - Inventors: Huijin Jang; Jaegu Yoo; Junsung Kim; Ganho Choi - Web page: https://patentgrep.com/patent/US12538101B2 ## CPC - H04W 4/06: Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services - H04W 28/06: Optimizing {the usage of the radio link}, e.g. header compression, information sizing {, discarding information (system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365)} - H04W 28/10: Flow control {between communication endpoints} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Disclosed are a multicast rule transformation apparatus and a method thereof. The multicast rule transformation apparatus according to an embodiment of the present invention performs an intersection transformation to convert a service flow rule for unicast transmission into a service flow rule for multicast transmission. ## Claims ### Claim 1 An apparatus for transforming a service flow rule (SF-Rule) for unicast transmission into a service flow rule for multicast transmission, the apparatus comprising: a rule decoder configured to generate a P4-aware service flow rule (hereinafter referred to as “P4a-Rule”) by removing duplications (OR) within a field from a service flow rule for unicast transmission to separate rule entries recognizable in the P4 language; a rule compiler configured to generate a P4-intersect service flow rule (hereinafter referred to as a “P4i-Rule”) by separating an overlapping part between the rule entries in the P4a-Rule, which is separated into the rule entries through the rule decoder, using an intersection algorithm; and a rule optimizer configured to generate a P4-optimized service flow rule (hereinafter referred to as “P4o-Rule”) by performing optimization to delete invalid rule entries in the P4i-Rule generated by the rule compiler. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the rule compiler performs a rule-entry intersection operation algorithm on the p4a-Rule according to a type of key field of a service flow rules to calculate an intersection part, and separates the calculated intersection part. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein, if the type of key field is Subnet Mask field, the rule compiler calculates the intersection part as a subnet mask with a smaller value among subnet masks being compared, and if the type of key field is Bit Mask field, the rule compiler calculates the intersection part as a bit mask with the most bits among bit masks being compared. ### Claim 4 (depends on 2) The apparatus of claim 2, wherein when calculating the intersection part based on whether key fields are identical (exact the same fields), the rule compiler calculates the intersection part as the identical value, and, if the result of the intersection operation is an empty set or an equal set, determines that a corresponding rule is an invalid rule, and the invalid rule is subject to removal by the optimizer. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the rule compiler performs a rule-entry intersection operation algorithm on the P4a-Rule with N rule entries to generate a P4i-Rule with a maximum of 2N rule entries, and the number of rule entries matches the total number of multicast output ports. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the rule compiler allows for overlap among the rule entries of the P4a-Rule obtained by compiling the R4a-Rule using the intersection algorithm, assigns an intersection priority to each rule entry, and assigns a higher priority to a rule entry with a larger number of sets included in an intersection. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the rule optimizer parses the P4i-Rule and removes invalid rule entries from the P4i-Rule to generate the optimized P4o-Rule, the invalid rule entries are rule entries that satisfy an empty rule condition or an equal rule condition, the empty rule condition refers to rule entries with no intersection in a matching field, and the equal rule condition refers to rule entries of the identical matching field. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein, when the equal rule condition is satisfied, the rule optimizer deletes a rule with fewer output ports (eg-id) among rule entries being compared. ### Claim 9 A method for transforming a service flow rule for unicast transmission into a service flow rule for multicast transmission by using a multicast rule transformation apparatus, the method comprising: obtaining a service flow rule for unicast transmission; generating a P4a-Rule by removing duplications (OR) within a field from the obtained service flow rule to separate rule entries recognizable in the P4 language; generating a P4i-Rule by separating an overlapping part between the rule entries in the P4a-Rule, which is separated into the rule entries, using an intersection algorithm; and generating a P4o-Rule by performing optimization to delete invalid rule entries in the generated P4i-Rule. ### Claim 10 (depends on 9) The method of claim 9, wherein in the generation of the P4i-Rule, a rule-entry intersection operation algorithm is performed on the P4a-Rule according to the type of key field of the service flow rule to calculate an intersection part, and the calculated intersection part is separated. ### Claim 11 (depends on 9) The method of claim 9, wherein in the generation of the P4i-Rule, a rule-entry intersection operation algorithm is performed on the P4a-Rule with N rule entries to generate a P4i-Rule with a maximum of 2N rule entries, and the number of rule entries matches the total number of multicast output ports. ### Claim 12 (depends on 9) The method of claim 9, wherein in the generation of the P4i-Rule, overlap among the rule entries of the P4i-Rule obtained by compiling the R4a-Rule using the intersection algorithm is allowed, an intersection priority is assigned to each rule entry, and a higher priority is assigned to a rule entry with a larger number of sets included in an intersection. ### Claim 13 (depends on 9) The method of claim 9, wherein in the generation of the P4o-Rule, the P4i-Rule is parsed and invalid rule entries are deleted from the P4i-Rule to generate the optimized P4o-Rule, the invalid rule entries are rule entries that satisfy an empty rule condition or an equal rule condition, the empty rule condition refers to rule entries with no intersection in a matching field, and the equal rule condition refers to rule entries of the identical matching field.