Transcript PPT Version

CAPWAP WG
CAPWAP Tunneling Protocol (CTP)
Inderpreet Singh
Chantry Networks
A division of Siemens AG
IETF 62, Minneapolis, MN
Base Functionality of CTP
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AP to AC Registration Functions
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Exchange of security credentials
Authentication mechanisms
Capability exchange
AP and AC session creation
Keep Alive
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Periodic poll messages to confirm connectivity
between AP and AC
Supports availability failover and alert triggers
Base Functionality of CTP
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Mobile Session Management
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Connection management
MU connection and disconnection services
 Encryption key management
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Policy exchange services
Encapsulation of User Data
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Encapsulated 802.3 data
Identifiers that assist in understanding policy
assignment (i.e. Network ID, WTP ID etc.)
TOS bit translation
Base Functionality of CTP
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AP Management
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Configuration
AP auto request on boot up
 Triggered from AC
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Statistics
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Periodic polling from AC
Firmware Upgrade Triggers
AP auto request on boot up
 Triggered from AC
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AP State Management
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Reset services, operational state
The Objectives
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Control, management and provisioning of
WTPs and ACs
Network layer agnostic (L2 or L3)
Radio Technology agnostic
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New requirement !!
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Local vs. Split MAC agnostic
The NON-Requirements
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AC Discovery
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Use DNS or
DHCP option or
SLP (unicast/multicast) or
Static Config
SW Image update mechanism
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Define sw update command messages
 SW Version
 SW server IP address
Utilize ftp or tftp
CTP Transport
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UDP based only
No distinction of L2 or L3
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No fragmentation/reassembly
No L2 specific discovery
Configuration and Statistics
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Assumption: All WTPs incorporate an SNMP
agent
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This is true for 802.11 Access Point reference designs,
but also assumed for future wireless APs
Every 802 standard has a MIB defined
Example: 802.11 Annex D defines 802.11 MIB already
Model all configuration and statistics on a MIB
and utilize the CTP transport to carry the OIDs
for configuration and statistics
Advantage
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Need to do MIB work anyway for CAPWAP
Flexible and modular for other wireless technologies
Local vs. Split MAC
ATT-MAC-INFO – This attribute consists of information pertaining
to the implementation of the wireless MAC layer in the WTP. This
in turn specifies to the AC the expected data type that will be
received. At this time only two types of MAC implementation are
supported, ie. Local MAC and Split MAC.
Type= 3
Length= 2 bytes
Value= MAC layer information as defined below:
0
1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RADIO-INDEX
|
MAC-TYPE
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where
RADIO-INDEX is a unique index of the enumeration of the number
of radios that the AP supports
MAC-TYPE is defined as
o Local MAC
= 1
o Split MAC
= 2
Local vs. Split (WTP)
+--+--+
+----+------+
<===>|
|
|
|
| CTP |<===========>|WirelessMAC|
Data
<--->|
|
|
|
+--+--+
+----+------+
^
^
|
+-----------+
|
|
|
|
|
Data (optional) <-------+--->| L2 bridge |<---+
|
|
+-----------+
Control
Local
Split
Control
Data
+--+--+
+----+------+
<===>|
|
|
Split
|
| CTP |<===========>| Wireless |
<--->|
|
|
MAC
|
+--+--+
+----+------+
Feedback?