Subject: [ippm] some improvement proposals to IOAM data draft

From: Haoyu song <[email-masked]>
Date: Mon, 25 Feb 2019 23:17:19 +0000

Dear authors,

Having reviewed the document, I think the following two ideas can help to improve the IOAM. Please consider. Thanks! 

(1)	Use a Data Template ID to replace the IOAM Trace Type. A data template is much more extensible and flexible than a bitmap. It allows IOAM to be used in different network scenarios (e.g., optical, wireless ...) and to support arbitrary data that might be of interest in the future. Each name space can freely defines its templates. The templates are configured to devices and only  a Template ID needs to be carried by an IOAM header. Different packets from a flow can carry a different template ID to collect a different set of data. 

(2)	Carry a Sequence Number (SN) field in the IOAM trace option header. SN can be used to identify any missing data, either because the original packet is dropped or the data itself, when being exported, is lost. It is useful to be used to find potential network failures and maintain the data integrity. With the help of SN, a device on the path can export the partial data to a collector to overcome the hardware or MTU constraints. The SN can be used as an packet identifier to correlated the partial data at the collector.

Best regards,
Haoyu