Unreliable inter process communication in Ethernet: Migrating to RINA with the shim DIF

27/04/2020 Sander Vrijders, Dimitri Staessens, Didier Colle, Mario Pickavet Ghent University Grasa i2CAT Boston University – iMinds Eleni Trouva, Eduard John Day, Lou Chitkushev 1

Communication between application



processes

Not to be confused with communication between interfaces  TCP/IP !!!

 Basic premise: All networking is inter process communication

and IPC only

 All communication goes through three phases:    Enrollment Flow allocation Data transfer 27/04/2020 2

Enrollment

    Creates/maintains/distributes/deletes the information within a layer that is needed to create instances of communication Often

ignored

in the current internet architecture Addresses, maximum packet size, … More well-formed enrollment phases in IEEE 802.11 (WiFi) and IEEE 802.1q (VLAN) 27/04/2020 3

Flow allocation

   Creates/maintains/deletes the shared state between

connection endpoint-ids

necessary to support the functions of the data transfer phase  For unicast: between

2 communication processes

Also often

ignored, forgotten

Without a flow allocation phase, all Protocol Data Units (PDUs) are implicitly accepted 4 27/04/2020

Data transfer

  The actual sending of data In the current architecture the other phases are often skipped  Immediately skipping to data transfer causes

unreliable inter process communication

27/04/2020 5

Examining the Ethernet Header

 Ethernet II: specification released by DEC, Intel, Xerox (hence also called DIX Ethernet)

Preamble MAC dest MAC src

7 bytes 6 bytes 6 bytes

802.1q header (optional)

4 bytes

Ethertype Payload

2 bytes 42-1500 bytes

FCS

4 bytes

Interfram e gap

12 bytes 27/04/2020 6

Examining the Ethernet header

 IEEE 802.3 Frame

Preamble MAC dest MAC src

7 bytes 6 bytes 6 bytes

802.1q header (optional)

4 bytes

Length

2 bytes

Payload FCS

42-1500 bytes 4 bytes

Interfram e gap

12 bytes  Combined with IEEE 802.2 (LLC)

DSAP

1 byte

SSAP

1 byte

Control

1-2 bytes

Information

M bytes (M>=0 ) 7 27/04/2020

Ethertype

   Identifies the

syntax

of the encapsulated protocol  Layers below need to know the syntax of the layer above Layer violation!

Same for the protocol id in the IPv4 header 27/04/2020 8

Consequences of using an Ethertype

 Also means only

one flow

can be distinguished between an address pair  The MAC address doubles as the connection endpoint-id 27/04/2020 9

Same problem with LLC?

   Source and Destination Service Access Points (SAPs) are the connection endpoint-ids  Allow for more than one flow to be distinguished between two communicating nodes Still

fixed endpoints

All traffic will still be accepted 27/04/2020 10

Recursive InterNet Architecture (RINA)

     New internetwork architecture Unified theory of networking A layer = a distributed application that provides IPC over a certain scope, called a Distributed IPC Facility (DIF) Recurse as much as needed Can be configured to a certain policy 27/04/2020 11

Architectural model

Application Specific Tasks Other Mgt. Tasks IPC Mgt. Tasks Multipl exing IPC Resource Mgt.

SDU Protec tion Inter DIF Directory System (Host) Appl. Process Mgmt Agemt System (Router) Mgmt Agemt Appl. Process System (Host) IPC Process IPC Process DIF IPC Process Shim IPC Process Shim DIF over TCP/UDP Shim IPC Process Shim IPC Process Shim DIF over Ethernet Shim IPC Process Mgmt Agemt Data Transfer SDU Delimiting Data Transfer Data Transfer Relaying and Multiplexing SDU Protection IPC API Data Transfer Control Transmission Control Control Retransmission Control Control RIB Daemon Flow Control Flow Control Flow Control RIB Layer Management CACEP Authentication CDAP Parser/Generator Enrollment Flow Allocation Resource Allocation Forwarding Table Generator Increasing timescale (functions performed less often) and complexity

Recursive InterNet Architecture

 Recognizes the three phases all communication goes through!

 Other advantages of RINA:    Inherent support for QoS Multihoming and mobility More secure 27/04/2020 13

Flow allocation in RINA

  Application A performs a flow allocation request Application B responds to this request   Accept Deny  If positive reply, a flow is created:   Port-id is assigned for further reference Connection (with CEP-id) is maintained in lower layer while there is active data transfer 14 27/04/2020

After flow allocation

27/04/2020 15

Flow allocation in TCP/IP

 UDP has the same problem as Ethernet     No flow allocation “Well-known ports”  security risk Either manual configuration needed for flow allocation Or use of other protocols (for instance SIP)  TCP has an incomplete flow allocation phase  But, overloads the uses of the TCP port (port-id and CEP-id)  another security risk  So, no decoupling of the flow allocation (port-id) and data transfer phase (CEP-id) 16 27/04/2020

Shim IPC process for 802.1q

    Interfaces a new model to a legacy implementation  shim Allows RINA DIFs to use it unchanged Only provides the capability of a legacy layer Simulates flow allocation 27/04/2020 17

Shim IPC process over 802.1q

    Spans a single Ethernet segment VLAN id is shim DIF name: joining the VLAN is considered enrolling in the shim DIF Uses Ethernet II: Only one user of the shim DIF Reuses the Address Resolution Protocol (ARP)  In RINA knowing which application is available at what address(es) is part of enrollment  For DIFs with small scope it can be part of flow allocation, just broadcast the allocate request 27/04/2020 18

Placement of the different PMs

27/04/2020 19

State diagram

27/04/2020 20

Conclusion

   Creating the shim DIF over Ethernet reveals something about the nature of layers  For reliable inter process communication, three phases have to be present Port-id and CEP-id have to be decoupled!

Port-ids seem to be a necessity for a clean separation of layers 27/04/2020 21

Questions ?

27/04/2020 Sander Vrijders [email protected]

www.ibcn.intec.ugent.be

Internet Based Communication Networks and Services (IBCN) Department of Information Technology (INTEC) Ghent University - iMinds 22