HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Slide title :32-35pt Color: R153 G0 B0 Corporate Font : FrutigerNext LT Medium Font to be used by customers and partners : Arial Slide text :20-22pt Bullets level 2-5: 18pt Color:Black Corporate Font : FrutigerNext LT Medium Font to be used by customers and partners : Arial Top right corner for field-mark, customer or partner logotypes The following nine groups of colors are an example of how our design colors can be used, please take note that you should only use one design color group per slide. For specific usage details, refer to the “Typesetting Standard”. Page 1 Diameter Peer Discovery Optimization Tina TSOU 

HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Slide title :32-35pt Color: R153 G0 B0 Corporate Font : FrutigerNext LT Medium Font to be used by customers and partners : Arial Slide text :20-22pt Bullets level 2-5: 18pt Color:Black Corporate Font : FrutigerNext LT Medium Font to be used by customers and partners : Arial Top right corner for field-mark, customer or partner logotypes The following nine groups of colors are an example of how our design colors can be used, please take note that you should only use one design color group per slide. For specific usage details, refer to the “Typesetting Standard”. Page 2 Diameter Peer Discovery Mechanism Diameter Clients discover nodes that provide diameter services in the network using the Peer Discovery mechanism. However they do not have a mechanism to discover the applications supported by the diameter servers. The client nodes do not know whether the intermediate node (agent) is connected to peers which support the Client Diameter Applications. With more and more diameter nodes getting added to the network, discovering the correct diameter peer will help in reducing the number of unnecessary message exchanges The following scenarios explain the problems that exist in the current peer discovery mechanism.

HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Slide title :32-35pt Color: R153 G0 B0 Corporate Font : FrutigerNext LT Medium Font to be used by customers and partners : Arial Slide text :20-22pt Bullets level 2-5: 18pt Color:Black Corporate Font : FrutigerNext LT Medium Font to be used by customers and partners : Arial Top right corner for field-mark, customer or partner logotypes The following nine groups of colors are an example of how our design colors can be used, please take note that you should only use one design color group per slide. For specific usage details, refer to the “Typesetting Standard”. Page 3 Case 1: Server identification using peer discovery Step 1: Client which supports Diameter Application X make DNS Query (using the existing peer discovery mechanism) DNS server sends P1, P2 and P3. Only P3 supports Diameter Application X. Client is unaware of this. Step2: CER/CEA handshake with P1 is failure because of no common applications Step 3: CER/CEA handshake with P2 is failure because of no common applications Step 4: CER/CEA handshake with P3 is Success Unnecessary CER/CEA handshake with P1 and P2

HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Slide title :32-35pt Color: R153 G0 B0 Corporate Font : FrutigerNext LT Medium Font to be used by customers and partners : Arial Slide text :20-22pt Bullets level 2-5: 18pt Color:Black Corporate Font : FrutigerNext LT Medium Font to be used by customers and partners : Arial Top right corner for field-mark, customer or partner logotypes The following nine groups of colors are an example of how our design colors can be used, please take note that you should only use one design color group per slide. For specific usage details, refer to the “Typesetting Standard”. Page 4 Case 2: Relays are involved Client queries DNS and gets Relay1, Relay2 and Relay 3 IP Addresses. Client successfully completes CER/CEA handshake with all the peers because relays advertise 0xFFFFFF application-id which indicates support of all applications Application Messages will not be routed by the relay in case the relay does not have connection to the servers which support the Diameter Application. Relays will send DIAMETER_UNABLE_TO_DELIVER. Application messages have to be resent multiple times to reach the destination server. For Inter-Operator Diameter Infrastructure, this problem can be avoided using relay pools on both sides which is generally not done in the intra-domain case. Servers are clusters like HSS which are front ended by relays. Typical scenario is when an app server like ATS has to connect to different servers like HSS, CCF and OCS

HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Slide title :32-35pt Color: R153 G0 B0 Corporate Font : FrutigerNext LT Medium Font to be used by customers and partners : Arial Slide text :20-22pt Bullets level 2-5: 18pt Color:Black Corporate Font : FrutigerNext LT Medium Font to be used by customers and partners : Arial Top right corner for field-mark, customer or partner logotypes The following nine groups of colors are an example of how our design colors can be used, please take note that you should only use one design color group per slide. For specific usage details, refer to the “Typesetting Standard”. Page 5 Solution Configure DNS with Diameter Applications Supported by each nodes. This needs to have another DNS query type instead of SRV or modify SRV RR’s which will provide the list of Application Ids supported by each peer. This needs to be agreed up on by the DNS Working group.