John DeHartComputer Science & EngineeringWashington University

www.arl.wustl.edu

GEC7: SPP TutorialCreating and Running

a Fast Path

3

Creating a Fast Path Instance Each code option requires its own Fast Path daemon

» For example: IPv4 Code option: ip_fpd» Runs on the GPE» Communicates with the RMP to cause the loading and initial configuration of the instance» Listens on two sockets for Local Delivery and Exception packets.» Local Delivery: Packets addressed to Fast Path’s MetaNet Address

• For example: ip_fpd responds to ICMP requests (ping) with appropriate ICMP response» Exception Pkts: Packets flagged by Fast Path as exceptions

• For example: ip_fpd receives TTL expired packets from Fast Path and generates appropriate ICMP message.

Parameters:» Name:» MetaNet Address:» Port Number:

Example:

ip_fpd --fpName fp1 --myIP 10.10.1.1 --myPort 5556 -- creates an IPv4 Fast Path with name fp1 and MetaNet address 10.10.1.1

4

Meta Interfaces Just like Routers have Interfaces, Meta-Routers have Meta-Interfaces Several Meta-Interfaces from different Meta-Routers can exist on the

same Physical Interface A Meta-Interface is defined by an SPP IP Address and UDP Port MetaNet Packets arrive at a Meta-Interface encapsulated in a UDP Tunnel It is the identification of the MI by IP Addr and UDP Port# that designates

a packet to be delivered to a specific Fastpath

UDP/IP Tunnel Hdr

UDP/IP Payload(MN Packet)

MN Packet Hdr(IPv4 Hdr in this case)

MN Packet Payload(IPv4 Pkt payload in this case)

5

scfg –cmd setup_fp_tunnel Command for setting up a Meta-Interface:

» scfg --cmd setup_fp_tunnel --fpid 0 --bw 10000 --ipaddr 64.57.23.182 --port 55555» MID=$?

• scfg returns value of Meta-Interface ID which can be assigned to a shell variable.» Sets up a MI

• For Fast Path 0• With a Bandwidth of 10 Mb/s (bw is specified in Kb/s)• On interface 64.57.23.182 (KANS ifn 1)• Using UDP Port 55555

6

Queues A Queue is Bound to a Meta-Interface QID: Queue Identifier

» 65536 queues shared across all MetaRouters and MetaInterfaces on each SPP» Number of queues allocated to a MetaRouter specified in Reservation» A MetaRouter’s QID space is number 0 through N-1 for a reservation of N queues.

Threshold» Maximum number of packets in queue before packet dropping starts

Bandwidth» Guaranteed minimum rate for traffic assigned to this queue:

• It can transmit more if there is no competition

Example:

scfg --cmd bind_queue --fpid 0 --miid 1 --qid_list_type 0 --qid_list 2-- binds qid 2 to Meta-Interface 1

scfg --cmd set_queue_params --fpid 0 --qid 2 --threshold 1000 --bw 10000-- configures qid 2 with threshold of 1000 pkts and bandwidth of 10Mb/s

7

Filters Filters in a Meta-Router route pkts from one Meta-Interface to another.

» Filters are installed on a specific Meta-Interface.• They apply to packets arriving on that Meta-Interface only

Filters have three parts:» Key (type, MN_Key)

• type=0: Normal• type=1: Bypass, used for packets coming from the slow_path which have already been classified.• MN_Key

– rxmi, daddr, saddr, dport, sport, proto

» Mask» Result (daddr, dport, qid, stats_index)

• Result is NOT MN specific• The qid identifies the outgoing MI since queues are bound to MIs• The (daddr, dport) pair defines the other end of the MI for outgoing pkt.• The stats_index allows us to monitor the number of packets forwarded by this filter.

Example ip_fpc --cmd write_fltr --fpid 0 --fid 4 \ --key_type 0 --key_rxmi 2 --key_daddr 10.10.1.3 \ --key_saddr 0 --key_sport 0 --key_dport 0 --key_proto 0 \ --mask_daddr 0xFFFFFFFF --mask_saddr 0 \ --mask_sport 0 --mask_dport 0 --mask_flags 0 \ --txdaddr 128.112.139.25 --txdport 21001 --qid 3 --sindx 4

8

Generating Data for a Fast Path Whatever application is used to generate MetaNet packets to be handled

by an SPP Fast Path, the MetaNet packets MUST be encapsulated in a UDP Tunnel.

When the MetaNet Protocol is IPv4, using a VPN, like OpenVPN, can be made to work for this.» The SPP does not act like an OpenVPN Server.» One of your end hosts can be the Server and others be clients.

• Once you have routes set up in your Fast Path to provide connectivity between all clients and the server, it works.

» BUT OpenVPN does not work with PlanetLab. • OpenVPN uses the tun/tap interface and PlanetLab already uses that for VNET.

Modify existing tools/applications» For example, it probably would not be too difficult to modify iperf to do it.

MetaNet Specific Application code.» You can write your own end host application code which does the UDP tunnel

encapsulation. For our Hands On exercises we will use a traffic generator program of our

own that has been enabled to do UDP Tunnel encapsulation.

9

Traffic Monitoring Stats Index

» A statistics index is associated with each Filter• One statistics index can be used across multiple filters to agregrate traffic statistics

» Each index has four counters associated with it:• Pre-Queue Packet Counter• Pre-Queue Byte Counter• Post-Queue Packet Counter• Post-Queue Byte Counter

Queue Length» Indexed by Queue Identifier (QID)» Two lengths associated with each Queue

• Length in Packets• Length in Bytes

Lookup

Filters

HeaderFormat

QueueManager

...

...

output

interfaces

Pre-Queue

Post-Queue

Queue Length