Blackadder ICN Prototype
T-110.6120 9.10.2012
Jimmy Kjällman
Ericsson Research, NomadicLab
Blackadder
• Realizes PURSUIT’s functional model for information-centric networking
Rendezvous Topology
Forwarding
Pub/Sub Service Model
SId
RId RId
Functional scoping Information scoping
Dissemination Strategy
Recursion
Information Structure
• Scopes, subscopes, information items
• Information is structured as a directed acyclic graph • IDs are (statistically) unique within a scope
– (Possibly) self-generated, flat labels – Same ID space for both subscopes and information
items • “Complete” identifier: Prefix + ID
– One or more paths starting from one or more graph’s root(s)
Information Structure
0001 0003
0001 0001 0002
0001
0001 0002 0003
AAA0 AAA1 AAA2 0002 AAA1
Scope
Information item
AAA2
Information ID : /0003/0002/AAA2
Scope ID : /0001/0001/0001, /0002/0001/0001, /0003/0001/0001
0002
0001
0002
0003
0001 0001
0001 0002
Original slides: George Parisis, Computer Laboratory, University of Cambridge, 2011
Core Functions
• Simplified example
Rendezvous
Topology
Forwarding P S
Dissemination Strategies
• Defines the methods used for implementation (of a scope) – Architectural components – Data formats – Governance structures – Etc.
• Can be “overridden” for sub-items – if permitted – Strategies have to be aligned
• Usually engineered at design time • Larger problem solutions through the assembly of
smaller ones
Service Model
• Publish/Subscribe
• For example: – publish_scope(id, prefix, strategy)
publish_info (id, prefix, strategy) – unpublish_scope(id, prefix, strategy)
unpublish_info (id, prefix, strategy) – subscribe_scope(id, prefix, strategy)
subscribe_info (id, prefix, strategy) – unsubscribe_scope(id, prefix, strategy)
unsubscribe_info (id, prefix, strategy)– publish_data(id, strategy, data, data_len)– getEvent(&event)
Blackadder Architecture
• Click is an external framework that Blackadder uses
Click
IPC Element
Communication Elements
/dev/eth0
App1 App2 App3 App4 AppN………………...
Rendezvous
Forwarding
Local Proxy
/dev/eth1 Raw IP Sockets
Topology Manager
Background Information: The Click Modular Router
• Open source platform for building packet processing configurations that consist of connected elements – Language for describing router configurations – Ready-made elements – Libraries for creating new elements as C++ classes
• Portable code – Kernel and userlevel – Linux, FreeBSD, Mac OS X, etc.
• Modular design approach – Reuse of elements in different configurations
(e.g., in different prototypes or experiments) • Basic operation: packets are pushed or pulled between
elements
Click Router Configuration
• Example: Ping (nothing to do with Blackadder, just illustrates a Click router)
define($DEV eth0, $DADDR 8.8.8.8, $GW $DEV:gw)FromDevice($DEV, SNIFFER false)
-> c :: Classifier(12/0800, 12/0806 20/0002)-> CheckIPHeader(14)-> ip :: IPClassifier(icmp echo-reply)-> ping :: ICMPPingSource($DEV, $DADDR)-> SetIPAddress($GW)-> arpq :: ARPQuerier($DEV)-> IPPrint-> q :: Queue-> ToDevice($DEV);
arpq[1] -> q;c[1] -> [1] arpq;
Blackadder Architecture
Click
IPC Element
Communication Elements
/dev/eth0
App1 App2 App3 App4 AppN………………...
Rendezvous
Forwarding
Local Proxy
/dev/eth1 Raw IP Sockets
Topology Manager
IPC Element
• Implements a Netlink socket for receiving pub/sub requests from applications (or an API library) and for sending back pub/sub events and published data – These are sent as messages through the socket – In user space, the IPC element utilizes the selection
mechanism provided by Click – In kernel space, the element receives sk_buffs in the context
of the running process – buffers are wrapped into Click packets that are later processed by a Click task
• Everything is asynchronous – like an event-based system
API (Service Model): Functions and Messages
• publish_scope(id, prefix, strategy) publish_info (id, prefix, strategy)
• unpublish_scope(id, prefix, strategy) unpublish_info (id, prefix, strategy)
• subscribe_scope(id, prefix, strategy) subscribe_info (id, prefix, strategy)
• unsubscribe_scope(id, prefix, strategy) unsubscribe_info (id, prefix, strategy)
• publish_data(id, strategy, data, data_len)
(These messages are only used node-internally)
ID Prefix ID length LIPSIN Identifier
Type
ID length
Strategy
ID length
1 1 Variable length Variable length1 1 LID size
ID LIPSIN Identifier
Type
ID length
Strategy
1 1 Variable length 1 LID size
Data
API: Events
• Start Publishing, Stop Publishing • New Scope, Deleted Scope
• Published Data
IDType
ID length
1 1 Variable length
ID
Type
ID length
1 1 Variable length
Data
Blackadder Architecture
Click
IPC Element
Communication Elements
/dev/eth0
App1 App2 App3 App4 AppN………………...
Rendezvous
Forwarding
Local Proxy
/dev/eth1 Raw IP Sockets
Topology Manager
Accessing the network
• Standard Click elements for network communication – ToDevice and FromDevice for directly sending and
receiving Ethernet frames • Suitable, e.g., when experimenting over high-speed LANs
– RawSocket for sending and receiving IP (UDP) packets over raw sockets
• Suitable, e.g., when experimenting in the PlanetLab testbed or VPNs
• IP network used as an underlay
Network Packet Format
LIPSIN Identifier
LID size
No. ID
s
ID1 len
gth
ID1
ID2 len
gth
ID2
IDn len
gth
IDn Payload
1 1 1 1
Blackadder Architecture
Click
IPC Element
Communication Elements
/dev/eth0
App1 App2 App3 App4 AppN………………...
Rendezvous
Forwarding
Local Proxy
/dev/eth1 Raw IP Sockets
Topology Manager
Forwarding
• Receives packets from the network communication elements – Matches the FID with all outgoing links and
forwards the packets – A separate LID is assigned to the “internal link”
between the Forwarding element and the Local Proxy Element
• Implements the notion of destination – Default method: LIPSIN
Sample forwarding configurations
• Click configurations – usually auto-generated
Forwarder (MAC, 1,1, 08:00:00:00:00:01, 08:00:00:00:00:11, 10000000000000000000000000000000000000000000000000000000000000001, 08:00:00:00:00:02, 08:00:00:00:00:12, 10000010000000000000000000000000000000000000000000000000000000002, 08:00:00:00:00:03, 08:00:00:00:00:13, 1000001000000000001000000000000000000000000000000000000000000000);fw[1] -> Queue(1000) -> ToDevice(eth0);fw[2] -> Queue(1000) -> ToDevice(eth1);FromDevice(eth0, SNIFFER false) -> Classifier(12/080a)[0] -> [1]fw;FromDevice(eth1, SNIFFER false) -> Classifier(12/080a)[0] -> [2]fw;Forwarder (IP, 1,1, 192.168.0.1, 192.168.0.2, 10000000000000000000000000000000000000000000000000000000000000001, 192.168.0.1, 192.168.0.6, 10000010000000000000000000000000000000000000000000000000000000002, 192.168.1.1, 192.168.1.2, 1000001000000000001000000000000000000000000000000000000000000000); fw[1] -> Queue(1000) -> RawSocket(UDP) -> IPClassifier(dst udp port 9999)[0] -> [1]fw;fw[2] -> Queue(1000) -> RawSocket(UDP) -> IPClassifier(dst udp port 9999)[0] -> [2]fw;
Blackadder Architecture
Click
IPC Element
Communication Elements
/dev/eth0
App1 App2 App3 App4 AppN………………...
Rendezvous
Forwarding
Local Proxy
/dev/eth1 Raw IP Sockets
Topology Manager
Local Proxy
• “The heart of a network node” – everything goes through it • Receives all pub/sub requests from applications and other Click
elements • Keeps track of
– Pending subscriptions – Advertised information items (and assigns FIDs)
• Receives – Published data and notifications about new or deleted scopes
• Pushes packets to subscribers (applications or Click elements) – Notifications to start or stop publishing data
• Pushes packets to one (of the potentially many) publishers
Local Proxy
• Applications are identified by the local Blackadder node by their Netlink source address (usually the process ID)
• Click elements are identified by the outgoing port number (from the Local Proxy to the specific element)
• These IDs are replaced in all pub/sub requests by a statistically unique Node Label (e.g., hash of MAC address)
Blackadder Architecture
Click
IPC Element
Communication Elements
/dev/eth0
App1 App2 App3 App4 AppN………………...
Rendezvous
Forwarding
Local Proxy
/dev/eth1 Raw IP Sockets
Topology Manager
RV Function
• The same element runs in all nodes • Every node can create an information structure that will be
known and maintained by the local RV function • Other nodes can send pub/sub requests to that node if they
know a path to it • Usual scenarios
– A network node (its RV function) maintains a local structure for IPC (node-local strategy)
– A network node (its RV function) maintains a structure accessible by physical neighbours (link-local strategy)
– One or more dedicated RV nodes run in a domain – end hosts know how to reach them (domain-local scenario)
RV IPC
• The RV Element access the world the same way applications do
• It subscribes to root scope FFFF where all pub/sub requests are published
• It publishes Topology Formation requests to scope FFFE to which the TM has subscribed
• Topology formation is required when: – A set of publishers need to be notified with
Forwarding IDs that point to a set of subscribers – A set of subscribers need to be notified about a new
or deleted scope
Blackadder Architecture
Click
IPC Element
Communication Elements
/dev/eth0
App1 App2 App3 App4 AppN………………...
Rendezvous
Forwarding
Local Proxy
/dev/eth1 Raw IP Sockets
Topology Manager
The Topology Manager
• An application – Calculates shortest paths in a network → Forwarding information
– Uses (e.g.) the igraph library for this • How the TM does IPC
– Subscribes locally to scope FFFE – Receives requests from the RV node as publications – Publishes responses directly to publishers and
subscribers using the Information ID /FFFD/destinationNodeID
– Utilizes an implicit rendezvous dissemination strategy where information is published with a specific FID
Blackadder Architecture
Click
IPC Element
Communication Elements
/dev/eth0
App1 App2 App3 App4 AppN………………...
Rendezvous
Forwarding
Local Proxy
/dev/eth1 Raw IP Sockets
Topology Manager
Dissemination Strategies • Currently 5 basic strategies are implemented
– These strategies are used for choosing the scope of information visibility in a network
1. Node-local – IPC, “localhost”
2. Link-local – Communication with neighbors on a link – Link IDs are provided by applications – Implicit RV or TM functions
Dissemination Strategies
3. Broadcast – Similar to link-local, but broadcast to (know)
neighbors 4. Domain-local
– RV and TM functions involved – End nodes need a FID for contacting the RV node – Publishers get FIDs (to subscribers) for individual
information items 5. Implicit rendezvous
– FID given in the publish data call – Mainly used by special components
(e.g., RV and TM)
A Blackadder Network
• All network nodes run the same software – Blackadder runs in user space or kernel space in the nodes
• Configurations can be different – End-nodes are configured to have link access (LID) and
access to dedicated rendezvous (RV) nodes (with an FID) – Dedicated forwarding nodes run only the forwarding element
• And other elements if additional functionality is required (e.g. caching)
– Dedicated RV and TM nodes • Any nodes can be RV nodes – an FID is required to reach them • TM nodes run a Topology Manager (TM) application
– A deployment tool can be used for generating configuration files and deploying them in a network
– Network attachment component for dynamic settings
Simple API Example
Publisher ba = Blackadder(True) ba.publish_scope(sid, “”, DOMAIN_LOCAL, None)ba.publish_info(rid, sid, DOMAIN_LOCAL, None) ev = Event(); ev.type = 0while ev.type != START_PUBLISH: ba.getEvent(ev) passwhile True: data = raw_input() ba.publish_data(sid+rid, DOMAIN_LOCAL, None, data, len(data))(This example uses a Python API that is wrapped on top of a C++ API library that translates API calls to messages that are passed through IPC sockets.)
Subscriber ba = Blackadder(True)ba.subscribe_info(rid, sid, DOMAIN_LOCAL, None) ev = Event()while True: ba.getEvent(ev) if ev.type == PUBLISHED_DATA: print ev.data[:ev.data_len]
Blackadder availability
• Open source (GPLv2 / BSD)
• Code, documentation, etc. • http://www.fp7-pursuit.eu/ • https://github.com/fp7-pursuit/blackadder/
• Current release: v0.2.1 (in GitHub) • Next release expected soon
BLACKADDER DEMO