# 0013: network headers
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- Stage: **0 (strawperson)** <!-- Update to reflect target stage. See https://elastic.github.io/ecs/stages.html -->
- Date: **2021-02-05** <!-- The ECS team sets this date at merge time. This is the date of the latest stage advancement. -->

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Stage 0: Provide a high level summary of the premise of these changes. Briefly describe the nature, purpose, and impact of the changes. ~2-5 sentences.
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We now have ~30 filebeat modules that can potentially record TCP
flags.  Often times these TCP flags are stored as a bit field in an
integer.  Searching if a bit is set in the integer is cumbersome and
it would be easier if there was an ECS field to hold these values.
Other network protocols have a similar need.

## Fields

We are proposing to add 6 new header groups for ip, ipv6, icmp, icmpv6, tcp & udp.

### IP
network.header.ip.flags : df, mf

### IPv6
network.header.ipv6.traffic_class
network.header.ipv6.flow_label

### ICMP
network.header.icmp.type
network.header.icmp.code
network.header.icmp.rest

### ICMPv6
network.header.icmpv6.type
network.header.icmpv6.code

### TCP
network.header.tcp.flags : ns, cwr, ece, urg, ack, psh, rst, syn ,fin
network.header.tcp.options

### UDP
network.header.udp.length
network.header.udp.checksum


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## Usage

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## Source data

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## Scope of impact

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## Concerns

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## Real-world implementations

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## People

The following are the people that consulted on the contents of this RFC.

* @leehinman | author

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## References

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### RFC Pull Requests

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* Stage 0: https://github.com/elastic/ecs/pull/1253

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