Thursday, July 19, 2018

ExtremeXOS 22.5.1 adds support Broadcom ASIC table utilization statistics

ExtremeXOS 22.5.1 is now available! describes added support in sFlow for "New data structures to support reporting on hardware/table utilization statistics." The feature is available on Summit X450-G2, X460-G2, X670-G2, X770, and ExtremeSwitching X440-G2, X870, X620, X690 series switches.

Figure 1 shows the packet processing pipeline of a Broadcom ASIC. The pipeline consists of a number of linked hardware tables providing bridging, routing, access control list (ACL), and ECMP forwarding group functions. Operations teams need to be able to proactively monitor table utilizations in order to avoid performance problems associated with table exhaustion.

Broadcom's sFlow specification, sFlow Broadcom Switch ASIC Table Utilization Structures, leverages the industry standard sFlow protocol to offer scaleable, multi-vendor, network wide visibility into the utilization of these hardware tables.

The following output from the open source sflowtool command line utility shows the raw table measurements (this is in addition to the extensive set of measurements already exported via sFlow by ExtremeXOS):
bcm_asic_host_entries 4
bcm_host_entries_max 8192
bcm_ipv4_entries 0
bcm_ipv4_entries_max 0
bcm_ipv6_entries 0
bcm_ipv6_entries_max 0
bcm_ipv4_ipv6_entries 9
bcm_ipv4_ipv6_entries_max 16284
bcm_long_ipv6_entries 3
bcm_long_ipv6_entries_max 256
bcm_total_routes 10
bcm_total_routes_max 32768
bcm_ecmp_nexthops 0
bcm_ecmp_nexthops_max 2016
bcm_mac_entries 3
bcm_mac_entries_max 32768
bcm_ipv4_neighbors 4
bcm_ipv6_neighbors 0
bcm_ipv4_routes 0
bcm_ipv6_routes 0
bcm_acl_ingress_entries 842
bcm_acl_ingress_entries_max 4096
bcm_acl_ingress_counters 68
bcm_acl_ingress_counters_max 4096
bcm_acl_ingress_meters 18
bcm_acl_ingress_meters_max 8192
bcm_acl_ingress_slices 3
bcm_acl_ingress_slices_max 8
bcm_acl_egress_entries 36
bcm_acl_egress_entries_max 512
bcm_acl_egress_counters 36
bcm_acl_egress_counters_max 1024
bcm_acl_egress_meters 18
bcm_acl_egress_meters_max 512
bcm_acl_egress_slices 2
bcm_acl_egress_slices_max 2
The sflowtool output is useful for troubleshooting and is easy to parse with scripts.

A convenient way to run sflowtool is to use Docker:
docker run -p 6343:6343/udp sflow/sflowtool

Ethernet Fabric Visibility

Ethernet Fabrics: Extreme Networks ExtremeFabric
Leaf and spine fabrics are challenging to monitor. The fabric spreads traffic across all the switches and links in order to maximize bandwidth. Unlike traditional hierarchical network designs, where a small number of links can be monitored to provide visibility, a leaf and spine network has no special links or switches where running CLI commands or attaching a probe would provide visibility. Even if it were possible to attach probes, the effective bandwidth of a leaf and spine network can be as high as a Petabit/second, well beyond the capabilities of current generation monitoring tools.

Fabric View solves the visibility challenge by using the industry standard sFlow instrumentation built into data center switches. Fabric View represents the fabric as if it were a single large chassis switch, treating each leaf switch as a line card and the spine switches as the backplane. The result is an intuitive tool that is easily understood by anyone familiar with traditional networks.

A demonstration can be run using Docker:
docker run --entrypoint /sflow-rt/ -p 8008:8008 sflow/fabric-view
Access the web interface on port 8008.
The first chart shows the largest TCP/UDP flows traversing the fabric (calculated from a continues stream of packet samples received from all the switches in the fabric). The chart updates every second, providing a real-time view of traffic crossing the fabric.
The last two charts are based on the hardware/table utilization statistics that are now implemented in ExtremeXOS, trending the maximum utilization of each table across all the switches in the fabric.


FabricView is one of a number of applications developed for sFlow-RT. Examples include: DDoS mitigation, Internet routing using top of rack switches, and other articles on this blog.
The sFlow-RT analytics engine receives a continuous telemetry stream from sFlow Agents embedded in network devices, hosts and applications and converts them into actionable metrics, accessible through APIs. Applications can be external, written in any language that supports HTTP/REST calls, or internal, using sFlow-RT's embedded JavaScript/ECMAScript.

Monday, July 16, 2018

Visualizing real-time network traffic flows at scale

Particle has been released on GitHub, The application is a real-time visualization of network traffic in which particles flow between hosts arranged around the edges of the screen. Particle colors represent different types of traffic.

Particles provide an intuitive representation of network packets transiting the network from source to destination. The animation slows time so that the particle takes 10 seconds (instead of milliseconds) to transit the network. Groups of particles traveling the same path represent flows of packets between the hosts. Particle size and frequency are used to indicate the intensity of the traffic flowing on a path.

Particles don't follow straight lines, instead following quadratic Bézier curves around the center of the screen. Warping particle paths toward the center of the screen ensures that all paths are of similar length and visible - even if the start and end points are on the same axis.

The example above is from a site with over 500 network switches carrying hundreds of Gigabits of traffic. Internet, Customer, Site and Datacenter hosts have been assigned to the North, East, South and West sides respectively.
The screen is updated 60 times per second for smooth animation. Active flow metrics are updated every second. Hovering over the screen freezes the animation, highlights the nearest particle, and displays details.

To try out the software, first create a configuration file to label axes and assign addresses for your network.
The above, particle.conf file, provides an example.

The simplest way to run the software is to use the pre-built Docker image.
docker run -p 8008:8008 -p 6343:6343/udp \
-v $PWD/particle.conf:/sflow-rt/particle.conf \
-e "RTPROP=-Dsystem.propertyFiles=particle.conf" \
Access the web interface on port 8008.
The Docker image also contains a random simulation of flows to demonstrate the software:
docker run -e "RTPROP=-Dparticle.demo=yes" \
-p 6343:6343/udp -p 8008:8008 sflow/particle
This particle visualization was inspired by experiments with Vizceral, see Real-time traffic visualization using Netflix Vizceral. Vizceral focuses on interactions between layered microservices.

Visualizing network traffic unique challenges that needed to be addressed. For example, in these examples the North, Internet, axis ( represents over 4 billion hosts - a number far greater than the number of pixels available on the screen. Instead of trying to represent each host individually, hosts are assigned a position proportional to their location in the range. For example, host is assigned a position half way along the axis. Assigning fixed positions to each host ensures that traffic between the hosts will always take the same path across the screen, making it easier to recognize patterns and identify changes.

Chances are you have network equipment that supports sFlow telemetry since the standard is widely supported by vendors, including: A10, Aerohive, ALUe, Allied Telesis, Arista, Aruba, Big Switch, Cisco, Cumulus, Dell, D-Link, Edge-Core, Extreme, F5, Fortinet, Huawei, IP Infusion, Juniper, Netgear, OpenSwitch, Pica8, Proxim, Quanta, SMC, ZTE, and ZyXEL. Give Particle a try and see how traffic flows on your network.

Wednesday, July 11, 2018

sFlow available on Juniper PTX series routers

sFlow functionality introduced on the PTX1000 and PTX10000 platforms—Starting in Junos OS Release 18.2R1, the PTX1000 and PTX10000 routers support sFlow, a network monitoring protocol for high-speed networks. With sFlow, you can continuously monitor tens of thousands of ports simultaneously. The mechanism used by sFlow is simple, not resource intensive, and accurate.  - New and Changed Features

The recent article, sFlow available on Juniper MX series routers, describes how Juniper is extending sFlow support to include routers to provide visibility across their entire range of switching and routing products.

Universal support for industry standard sFlow as a base Junos feature reduces the operational complexity and cost of network visibility for enterprises and service providers. Real-time streaming telemetry from campus switches, routers, and data center switches, provides centralized, real-time, end-to-end visibility needed to troubleshoot, optimize, and account for network usage.

Analytics software is a critical factor in realizing the full benefits of sFlow monitoring. Choosing an sFlow analyzer discusses important factors to consider when selecting from the range of open source and commercial sFlow analysis tools.