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MobilityFirst Prototype
Table of Contents
Overview
Components
MobilityFirst Router
The router prototype is Linux-based, and, as depicted in Figure 1, follows a two-level emulation setup: a fast data path handled by a forwarding engine, and a control path implemented at user-level. The Click Modular router will embody the forwarding engine in our primary prototype and will run on commodity x-86 hardware. Alternately, routing and network support services can be implemented as modules within an OpenFlow-based architecture within a central controller to direct one or more forwarding switches. Performance may also be further boosted by porting forwarding components into programmable network hardware such as the 1Gbit or 10Gbit NetFPGA cards, to achieve line-rate implementations.
In our Click-based implementation, C++ data-path elements will implement the following: 1.) a reliable link-level, hop-by-hop transport manager, 2.) a fast, storage-aware route lookup module, and 3.) a cache manager to support in-network caching of content. Underlying x-86 hardware may support one or more wired/wireless interfaces, and commensurate memory and processing resources to sustain reasonable data rates across each interface.
User-level processes either within a framework such as the extensible open source routing platform (XORP), or as standalone processes, will implement routing and management services, and network-support services such as the name resolution service. Messages exchanged by these user-level services with other routers are forwarded through the Click engine through host receive and transmit queues. Updates to the routing information base computed by the control plane, is pushed down promptly to the forwarding engine for up-to-date next-hop lookups.
MobilityFirst Host Stack
In our clean slate approach to networking, we propose a new socket API for applications. This API along with the stack implementation of MF protocols will support name resolution, send/receive of messages, specification for intentional data receipt, context and location management, content retrieval, as also querying of network state to determine link and path quality information. This API is implemented as user-level libraries that applications can link to. As part of the prototyping and evaluation, we plan on programming both novel and traditional applications to use this new API and protocol stack.
MobilityFirst Network API
Global Name Resolution Service (GNRS)
GNRS(Rutgers) Implementation Details
Releases
No public releases yet.
ORBIT Evaluation
Early versions of the prototype MobilityFirst (MF) network consisting of: (1.) Click-based router, (2.) a distributed name resolution service, and (3.) client network API and host protocol stack are available for evaluation on the ORBIT testbed. The steps involved in evaluating sample configurations are listed below. Before you begin, it is suggested that your familiarize yourself with the OMF framework, which is used to setup and orchestrate these experiments.
Deploying MobilityFirst on ORBIT nodes
The deployment can be done in one of the following ways:
- Installing an MF release (tarball or SVN revision) and dependencies on a base ORBIT image
- Imaging ORBIT nodes with a pre-established MF disk image
MF Disk Images for ORBIT
An MF disk image contains all components (router, gnrs, and client stack and network API library - sources and precompiled binaries) and can be installed on nodes using OMF tools.
All images listed below are stored at repository1.orbit-lab.rutgers.edu:/export/omf/omf-images-5.2: Images Currently In Use
| Image Name | Created on | MF Release | Description |
| mf-proto-gec12.ndz | 11-1-2011 | unnamed | End-to-end integrated layer 2 with MF Network API, MF host stack and an MF Router with GSTAR. Router partially integrated with locally running GNRS server |
| mf-proto-trial3.ndz | 9-22-2011 | unnamed | MF node with router, gnrs and client modules - OMF script configures node function. GUID assignment and topology choice from OMF script |
Loading a particular image is done using the 'load' command:
> omf load <node-set> <image-name> e.g., > omf-5.X load [[1,1], [1,2], [1,3]] mf-proto-1.0.ndz
'X' in the command above refers to the version of OML control framework. Presently, 5.2 and 5.3 are most used.
Inside a MobilityFirst Image
Code Base
The image holds the prototype code base under /usr/local/mobilityfirst/code. It has the following top-level directories:
- click - Router elements implementing storage-aware routing, hop-by-hop reliable link-level data transport, and interface to GNRS service. This also has elements that implement Click-based sender and receiver applications.
- gnrsd - C++ implementation of a GNRS server, and an interactive GNRS client.
- client - C implementations of client API and stack that compile for Linux and Android platforms. Also has sample sender and receiver applications using the API
- eval
Binaries, Configuration Files
- bin - compiled binaries go here
- conf - config files from across sub projects, incl. click and gnrs configurations
- scripts - e.g., to initialize Click execution
- topology - definition files used within the MF router to enforce connectivity among nodes
Also installed on this image are the dependencies for the router, gnrs, and client components. A complete list of installed dependencies can be found in the README accompanying the code base.
Boot Script
The image also contains a boot script (/etc/init.d/mf-proto) that can be used to automate the update/compile functions. It updates the local codebase to the latest release from MF SVN, (TODO - auto updating is currently disabled, pending the creation of an anonymous account access to MF SVN), and then compiles and installs Click and other MF component binaries as described above. Excerpt below from the boot script shows the update and compilation of the click router:
... MF_DIR=/usr/local/mobilityfirst MF_CLICK_ELEMENTS_DIR=$MF_DIR/code/click/elements CLICK_DIR=/usr/local/src/click #update mobilityfirst prototype code base cd $MF_DIR/code #auto-update disabled pending anonymous account #svn update #Compile user-level click after copying MF's click elements into click codebase rsync -vt $MF_CLICK_ELEMENTS_DIR/gstar/* $CLICK_DIR/elements/local cd $CLICK_DIR ./configure --disable-linuxmodule --enable-local make elemlist make install ...
The output of the boot script is appended to /var/log/mf-proto-boot.log.
Updating or Customizing an Existing MF Image
The installed MF source can be updated to a latest release either from the SVN or using a release tar ball. If updating to latest SVN version, you simply run the update command from under the /usr/local/mobilityfirst/code dir. If customizing to a particular MF version from SVN or using a newer tar ball, first delete contents under the code dir before installing. Similarly, one can also update 3rd party components like Click while creating an updated MF image.
For compiling an updated code base, we currently have a simple 'make' bash script (/usr/local/mobilityfirst/code/boot/mf-proto) that combines several steps. Usually, the compiled MF binaries are installed under /usr/local/mobilityfirst/bin. However, the 3rd party components we use are in various locations. For example the source for Click modular router is under /usr/local/src/click, and it's compiled binary ends up under /usr/local/bin. Therefore, before building the Click-based router, the MF-Click elements that implement the protocol stack are to be installed under Click's designated source dir (/usr/local/src/click/elements/local to be specific). So, the bash compilation script does all such steps for the router, gnrs, host protocol stack and network API library components, placing the compiled binaries in proper locations.
Once the source has been updated, the following compiles and installs binaries. Alternately, one can also update just individual components and run the local make and copy binaries to proper locations.
> /usr/local/mobilityfirst/code/boot/mf-proto #compilation script
Once ready with all upgrades and want to create a new MF image, you have to run an ORBIT 'prepare' script to among other things ensures the package manager caches are cleaned, and interfaces are configured appropriately when creating a general disk image that can be booted on a variety of hardware nodes.
> cd /root > ./prepare.sh #common ORBIT script to prepare file systems for creating an image
The prepare.sh script above will also log you out and turn the node off, following which you can save the newly created image by using the OMF save command:
> omf-5.X save [1,1]
The resulting image can be found at repository1:/export/omf/omf-5.X/ and can be used to image nodes for subsequent experiments.
Configuring and Running MobilityFirst Experiments
While custom scripting can be used to execute an experiment, OMF has all necessary functionality to reliably configure and repeat experiments on the ORBIT testbed. Both the configuration details (what nodes run what applications with what parameters) and the experiment execution control (when to run what) can be specified within a ruby script using omf syntax. Refer to OMF User Guide to get familiar with writing OMF scripts. In the next section, we present several sample scripts to get you started with MF network experimentation.
Once you define an experiment script, and have loaded the MF image on the nodes that will run MF components, you run the experiment using the 'exec' command:
> omf-5.X exec my-mf-expt.rb
The omf runtime reports any failure to bring up components. For more detailed information, refer to the logs created by MF components - all located under /var/log. Additionally, MF components (only Click-based router presently) are instrumented to report key statistics which are then logged to relational tables hosted on an OML server co-located with the testbed. Section on 'OML-based Monitoring' has more details.
Sample OMF Scripts for ORBIT
Test Config 1: Sender-Router-Receiver
Below is the simple topology:
S ---- MFR ---- R S-Sender Host, MFR - MobilityFirst Router, R - Receiver Host
The topology in these experiments is enforced within the Click implementations by a GUID-based connectivity graph specified by a topology file passed to click. The following lines in the topology file define the above graph:
#syntax: <node-GUID> <neighbor-count> <neighbor-GUID1> [<neighbor-GUID2>] ... 1 1 2 2 2 1 3 3 1 2
Files: OMF script | topology file
Test Config 2: Multiple Senders and Receivers
Below is the topology:
S2
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S1 ---- MFR1 ----- MFR2 ---- MFR3 ---- R1
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R2
S-Sender Host, MFR - MobilityFirst Router, R - Receiver Host
Files: OMF script | topology file
GENI Evaluation
GENI, an NSF-funded proposal for a global environment for network innovation, is a multi-group collaborative effort to realize an at-scale experimental network infrastructure that is rich (i.e., with wired and wireless resources, commercial and experimental platforms) and allows for deep programmability.
ProtoGENI is the prototype implementation and deployment of GENI. ProtoGENI is also the control framework for a number of GENI resources currently deployed on the national backbone and at several participating campuses. It is worth noting, however, that there are several GENI deployments that use other control frameworks and experimentation across ProtoGENI and these deployments is currently set up via personnel coordination/manual configuration.
The following links provide the basic information to learn about ProtoGENI and to get started with experimentation:
- ProtoGENI Tutorial with basics on
- Creating an account with one of the Clearing houses (e.g., Utah Emulab or BBN)
- Setting up certificate (with managers) and key-based (with individual hosts) authentication and authorization
- Steps and test scripts for finding and reserving resources on ProtoGENI
- Quering and Reserving Resources can be done using either of following:
- Flack: a graphical map interface. Flack Manual
- Omni: a command line tool for reserving resources across control frameworks
- ProtoGENI Test Scripts that can be used as starting point to get familiar with ProtoGENI interfaces and to ensure account is set up right
