Blackadder
ICN Prototype
T-110.6120
9.10.2012
Jimmy Kjällman
Ericsson Research, NomadicLab
Blackadder
• Realizes PURSUIT’s functional model
for information-centric networking
Pub/Sub Service Model
Dissemination
Strategy
Rendezvous
Topology
Forwarding
SId
RId
RId
Functional scoping
Information scoping
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
Scope
0001
0002
0003
Information
item
AAA1
0002
0001
0001
0002
0001
0001
0002
AAA0
AAA1
0003
Information ID : /0003/0002/AAA2
Scope ID : /0001/0001/0001, /0002/0001/0001, /0003/0001/0001
Original slides: George Parisis, Computer Laboratory, University of Cambridge, 2011
AAA2
Core Functions
• Simplified example
Rendezvous
Topology
P
Forwarding
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
App1
App2
App3
App4
………………...
AppN
Click
IPC Element
Rendezvous
Local Proxy
Topology
Manager
Forwarding
Communication Elements
/dev/eth0
/dev/eth1
Raw IP Sockets
• Click is an external framework that Blackadder uses
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
FromDevice@1
c
Classifier
• Example: Ping
(nothing to do with Blackadder,
just illustrates a Click router)
CheckIPHeader@3
ip
IPClassifier
ping
ICMPPingSource
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;
SetIPAddress@6
arpq
ARPQuerier
IPPrint@8
q
Queue
ToDevice@10
Blackadder Architecture
App1
App2
App3
App4
………………...
AppN
Click
IPC Element
Rendezvous
Local Proxy
Topology
Manager
Forwarding
Communication Elements
/dev/eth0
/dev/eth1
Raw IP Sockets
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
•
subscribe_scope(id, prefix, strategy)
subscribe_info (id, prefix, strategy)
•
unsubscribe_scope(id, prefix, strategy)
unsubscribe_info (id, prefix, strategy)
1
Variable length
1
Variable length
1
LID size
ID
Prefix ID length
LIPSIN Identifier
1
1
Variable length
1
LID size
ID length
ID
Strategy
publish_data(id, strategy, data, data_len)
Type
•
1
Strategy
unpublish_scope(id, prefix, strategy)
unpublish_info (id, prefix, strategy)
ID length
•
ID length
publish_scope(id, prefix, strategy)
publish_info (id, prefix, strategy)
Type
•
LIPSIN Identifier
(These messages are only used node-internally)
Data
API: Events
1
1
Variable length
Type
ID length
• Start Publishing, Stop Publishing
• New Scope, Deleted Scope
ID
1
1
Variable length
Type
ID length
• Published Data
ID
Data
Blackadder Architecture
App1
App2
App3
App4
………………...
AppN
Click
IPC Element
Rendezvous
Local Proxy
Topology
Manager
Forwarding
Communication Elements
/dev/eth0
/dev/eth1
Raw IP Sockets
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
1
LIPSIN Identifier
ID1 length
1
ID1
1
ID2
IDn length
1
ID2 length
LID size
No. IDs
Network Packet Format
IDn
Payload
Blackadder Architecture
App1
App2
App3
App4
………………...
AppN
Click
IPC Element
Rendezvous
Local Proxy
Topology
Manager
Forwarding
Communication Elements
/dev/eth0
/dev/eth1
Raw IP Sockets
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, 1000000000000000000000000000000000000000000000000000000000000000
1, 08:00:00:00:00:02, 08:00:00:00:00:12, 1000001000000000000000000000000000000000000000000000000000000000
2, 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, 1000000000000000000000000000000000000000000000000000000000000000
1, 192.168.0.1, 192.168.0.6, 1000001000000000000000000000000000000000000000000000000000000000
2, 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
App1
App2
App3
App4
………………...
AppN
Click
IPC Element
Rendezvous
Local Proxy
Topology
Manager
Forwarding
Communication Elements
/dev/eth0
/dev/eth1
Raw IP Sockets
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
App1
App2
App3
App4
………………...
AppN
Click
IPC Element
Rendezvous
Local Proxy
Topology
Manager
Forwarding
Communication Elements
/dev/eth0
/dev/eth1
Raw IP Sockets
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
App1
App2
App3
App4
………………...
AppN
Click
IPC Element
Rendezvous
Local Proxy
Topology
Manager
Forwarding
Communication Elements
/dev/eth0
/dev/eth1
Raw IP Sockets
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
App1
App2
App3
App4
………………...
AppN
Click
IPC Element
Rendezvous
Local Proxy
Topology
Manager
Forwarding
Communication Elements
/dev/eth0
/dev/eth1
Raw IP Sockets
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
Subscriber
ba = Blackadder(True)
ba = Blackadder(True)
ba.publish_scope(sid, “”, DOMAIN_LOCAL,
None)
ba.publish_info(rid, sid, DOMAIN_LOCAL,
None)
ba.subscribe_info(rid, sid, DOMAIN_LOCAL,
None)
ev = Event(); ev.type = 0
while ev.type != START_PUBLISH:
ba.getEvent(ev)
pass
ev = Event()
while True:
data = raw_input()
ba.publish_data(sid+rid, DOMAIN_LOCAL,
None, data, len(data))
while True:
ba.getEvent(ev)
if ev.type == PUBLISHED_DATA:
print ev.data[:ev.data_len]
(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.)
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
S1
Laptop
P
F
Bridge
Multicast forwarding
S2
Video stream
Virtual machines
running in the laptop
How it works (roughly)
publish scope
publish info
recv
pub
RV
subscribe info
compute
paths
proxy
TM
library
proxy
library
FID
Blackadder
Blackadder
publish data
send
sub
Anything else?
Questions?
Thank you!