1 / 10

QoS Interactions

QoS Interactions. Interaction of AES Message Integrity Check Processing with Quality of Service. Overview. AES encryption modes provide integrity protection of portions of the MAC header

cskaggs
Download Presentation

QoS Interactions

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. QoS Interactions Interaction of AES Message Integrity Check Processing with Quality of Service Paul Lambert, Woodside Networks, Inc.

  2. Overview • AES encryption modes provide integrity protection of portions of the MAC header • 2.2 draft and other AES proposals protect different header fields and include different information in the ‘nonce’ • QoS processing has impact on nonce and integrity processing • This proposal recommends necessary requirements for nonce and integrity processing Paul Lambert, Woodside Networks, Inc.

  3. Nonce Processing • Nonce / key pair must be unique • Nonce includes Replay Counter (a.k.a. Packet Number) • QoS processing requires unique replay counter per transmit side QoS-TCID • To prevent duplication of nonce/key pair the QoS-TCID must be included in the nonce! Paul Lambert, Woodside Networks, Inc.

  4. Replay Counter • Individual replay counters must be supported per QoS Traffic Class • QoS operation would delay some packets making window size for a single counter indeterminate • Checking monotonicity of a single transmit counter limits window size to one (Russ’s proposal) • So … Replay counters per QoS Traffic Class must be supported (already in draft) Paul Lambert, Woodside Networks, Inc.

  5. MIC’ing the Sequence Number and QoS • 11-02-144r1 (aka CCM) proposed inclusion of Sequence Control field in AES MIC • Sequence Number (in Sequence Control) is sequential over-the-air • QoS scheduling makes the order of transmission indeterminate • So … Sequence Number can not be added until packets are pulled of QoS queues for transmission Paul Lambert, Woodside Networks, Inc.

  6. No MIC on Sequence Number with QoS • With the Sequence Number put on just before transmission, a message integrity check would have to put on just prior to transmission • Low latency requirements for QoS transmission prevent just-in-time encryption • Encryption processing must allow encrypted packets to be placed in QoS queues • Sequence number can NOT be part of message integrity • Very important to not include SN to support QoS and software implementations Paul Lambert, Woodside Networks, Inc.

  7. MIC and Nonce Summary • QoS-TCID must be included in AES Nonce • Replay counter / Packet Number counter is unique per transmit QoS Traffic Class • The Sequence Number Field should NOT be included in the MIC calculation Paul Lambert, Woodside Networks, Inc.

  8. Unicast Replay Verification • Current draft (2.2 section 8.3.1.3.4.11) defines replay processing with STA counters being odd and AP counters being even. • This will not work for iBSS • This is not necessary for nonce uniqueness since the SA is already included Paul Lambert, Woodside Networks, Inc.

  9. AES/WRAP Unicast Replay-Counter Processing • WRAP replay counter processing shall provide a unique counter per QoS traffic class • Current limitations on counter (odd-even increments) shall be removed and replaced with unique counters that increment by one. Paul Lambert, Woodside Networks, Inc.

  10. WRAP Layering in 802.11 MAC MSDU Fragmentation WRAP Processing Replay Counter Replay Counter Replay Counter QoS Queues MPDU MPDU MPDU MPDU MPDU Transmit Sequence Counter Paul Lambert, Woodside Networks, Inc.

More Related