Tactical Wireless Communications and Networks: Design Concepts and Challenges

9.3 ICD I: Plain Text IP Layer to HAIPE

As mentioned in Chapter 8, this ICD covers the user traffic flow. ICD I addresses those capabilities performed by the plain text IP layer that do not require the peer plain text IP layer to have special protocol or software modules. An example of an ICD I capability is the selection of the size of the plain text IP layer packets sent to HAIPE for encryption.

The packet payload size can be large with data and video packets (the video packets contain the I-frame information). The maximum transmission unit (MTU) of Ethernet,¹¹ which was created to maximize the ratio payload size to header size, must be revisited with HAIPE encryption.¹² HAIPE encrypts the entire plain text IP packet, including its headers, and makes the encrypted packet the payload of the cipher text IP packet as shown in Figure 9.6 for the IP v4 case. HAIPE implementation of IP SEC ESP tunnel mode can add a considerable number of bytes¹³ to the plain text IP packet size.

Figure 9.6 HAIPE use of IPSec in tunnel mode increases the plain text packet size.

The use of the MTU size for standard IP, over Ethernet protocols, needs to be adjusted in the plain text IP layer to avoid fragmenting the cipher text packets.

Ethernet V2 defines the MTU as 1500 bytes. If we need 20 bytes for the Ethernet header, the plain text IP layer or the end user TCP layer creates a packet with the payload ...