-
Ericsson
Evolved IP Network Solution 2015 Update
Multi-Service, LTE-A Readiness and Converged Transport
Report
IntroductionFollowing the success of the 2014 EANTC reportfor
Ericsson’s Evolved IP Network, the vendorcontracted EANTC to create
an updated version for2015 covering additional solution
capabilities andnewly available products.
The 2014 report accompanied the initial release ofEricsson’s
Evolved IP Network solution. Ericssonexplained that they take a
holistic approach indesigning and supporting their end-to-end
solution.This approach incorporates protocol and softwareuniformity
across any node in the solution.
Ericsson spent the year since our last reportexpanding its IP
portfolio, developing new capabili-ties and consolidating the
end-to-end solution story.Since the solution has two major software
releasesper year, we had the opportunity to explore capa-bilities
planned to be released around the sametime as this report. By
executing this second testphase, EANTC has now tested the complete
Eric-sson Evolved IP Network solution including allelements of the
SSR 8000 router family.
In this report we explore the following main points:
• Network design consistent with previous solutiontest
report
• True multi-service router capabilities with BNG,IPsec,
Ethernet and IP/MPLS services are verified
• Service support for fixed and enterprise customers
• Readiness for LTE-Advanced
• 100GbE interfaces and the new Ericsson SSR8004 router are
tested
• Updated Microwave solution MINI-LINK TN istested
• Network Management System (NMS) is extensivelyexplored
Background
Our previous test report highlighted the end-to-endcapabilities
of the solution starting with the multi-standard base stations,
progressing through themicrowave radios and exploring the IP/MPLS
capa-bilities. We also spent time exploring the packetclock
synchronization and high availability capabil-ities of the
solution.
The 2014 report was not the first time EANTC engi-neers have
tested Ericsson's products. Ericsson hasbeen supporting EANTC's
interoperability show-cases since our 2008 Mobile Backhaul test
event,and over the years has shown interoperability inareas such as
clock synchronization, IPv6 IP/MPLSand MPLS-TP. All the reports are
available onEANTC's web site.
Test Highlights
Verified multi-service support on Ericsson SSR 8000 family
Measured 6,000 VPLS instances with 996,000 MAC addresses
Demonstrated 96,000 subscribers supported on a single line
card
Tested complete service life cycle toolkit capabilities
Recorded phase stability consis-tently under 1.1
microseconds
Confirmed up to 25%a improve-ment in microwave link
utilization
a. For 82 bytes frames
EANTC Test Report: Ericsson Evolved IP Network Solution 2015
Update – Page 1 of 12
-
Having gotten to know the solution well, we pushedEricsson to
demonstrate that the Evolved IP Networksolution is truly
multi-service by supporting residen-tial, business and mobile
subscribers on a singledevice. We also felt that it was imperative
toexplore additional clock synchronization functionssince, with the
growing deployment of Long TermEvolution (LTE) and early
deployments of EvolvedMultimedia Broadcast Multicast Service
(EMBMS),a robust packet clock network is essential fortrouble-free
mobile network operations.
Ericsson re-stated IP networks as one of theirtargeted areas in
their Q4 2014 report, with salesgrowth of over 10% in all targeted
areas. Ericssonalso reported twelve new SSR 8000 contractsduring Q4
2014, of which two were for fixednetworks, bringing their total for
such contracts wonto 146. It is evident from the breadth of
newfeatures and capabilities that Ericsson brought tothis update
test, that Ericsson was not simply restingon their laurels. We see
the continuous vendorcommitment and it seems that the service
providercustomers are indeed responding.
Tested Devices
The network design, including its layering andguiding
principles, remained consistent between the2014 and 2015 tests.
This not only made our lifesimple when designing the tests, but
also attested toEricsson's commitment to their service
providercustomers. Clearly, a service provider thatpurchases the
Evolved IP Network solution from Eric-sson, would not expect to
have to fundamentallychange its network a year later.
What did change though was the range of devicesprovided for
test. While in 2014 we had variants ofthe all-outdoor MINI-LINK PT
family in the test, thistime around, Ericsson chose to bring the
chassis-based MINI-LINK TN in addition to the MINI-LINKPT. The rest
of the devices in the access were allEricsson SP 415 or SP 420
routers (the differencebetween the two being port count).
Figure 1: End-to-end Network Topology
MINI-LINK PT
SP 420MINI-LINK TN
Business
RBS
Microwave Link10 Gigabit Ethernet
100 Gigabit Ethernet
Ixia Traffic Generator
Access Network
GPS Antenna
RBS
Management Network
SP 415
Southbound Interfaces
Aggregation NetworkCore Network Management Network
Clock link — Freq.1PPS Link
Anue Freq./Phase Analyzer
Clock Link — ToD
Emulated Access
1 Gigabit Ethernet
SP 420
Access
Access LANTIME M3000
12:50:00
Internet
SP 420
(BNG & IPsec)
IPsecBusiness
DSL
TimeProvider 2700
12:50:00
AggregationAccess
SSR 8010
Emulated Internet
RBS 6501
Grandmaster12:50:00
Microsemi
Meinberg
IPT NMS
Business
SSR 8010
SSR 8010
SSR 8010
DSL
SSR 8004
Boundary Clock
Business
SP 420
SSR 8004
EANTC Test Report: Ericsson Evolved IP Network Solution 2015
Update – Page 2 of 12
-
Apart from the notable addition of the newestcommercially
available router – the SSR 8004, therest of the devices were the
same as in the previoustest. Under the hood however, there were
quite afew new components. For the first time we testedEricsson's
100GigabitEthernet line card, the SSCand BNG cards, and an updated
alarm/switchfabric card that enables the SSR products to
supportphase synchronization on existing line cards.
Test Equipment
This time we executed the complete project atEANTC's lab in
Berlin, Germany. Our lab adminis-trator was overjoyed to welcome
boxes and boxesof Ericsson devices which were eventually
installedin 4 racks. Ericsson sent a team of engineers toBerlin who
spent 6 weeks together with EANTC'stest engineers.
The testing was supported by Ixia who provided amultitude of
test devices. In addition to the layer 2/3 testers, we also
required IPsec and BNG trafficgenerators. Consequently, the Ixia
XG12 we hadwas filled with cards such as the Lava AP40/100G,FlexAP
10G, LSMXMDC and STX4. To measure theclock quality we used Ixia's
Anue 3500. In fact, alltests in the project, regardless of their
network layeror interface speed, were supported by the same
testvendor.
The tests required that test engineers from bothEANTC and
Ericsson possessed more than singlenetworking layer expertise; it
required them tounderstand the interaction between multiple
layers.While IP/MPLS traffic was being emulated end-to-end, we also
registered BNG subscribers and IPsectunnels – all tasks that would
traditionally be takenby different operational teams.
Multi-Service Capabilities
The Ericsson Smart Services Routers (SSR) are devel-oped fully
in-house and are built upon the combina-tion of Ericsson's
fixed/mobile telecom heritageand Silicon Valley-based IP
competency. After wecompleted the test project in 2014, we asked
Eric-sson a seemingly innocent question – what is so'smart' about
these routers? Ericsson explained thatan example of the smart
capabilities is the ability tocollapse different services into a
single router (withan appropriate combination of cards).
We were intrigued and, for the purposes of theseupdated tests,
asked Ericsson to include these linecards in a typical combination.
Ericsson chose toinclude two functions in addition to the
IP/MPLSservices that were already planned for the test:IPsec
Security Gateway and Broadband NetworkGateway (BNG).
The BNG functionality allows a service provider toterminate
residential wireline subscribers on theEricsson router in the
aggregation network. In thesame router, IPsec tunnels, expected to
be estab-lished by the mobile base stations, could also
beterminated. Of course additional functions andapplications could
have been added, but we had tolimit the efforts somewhere and felt
that the threeservices we could emulate were sufficient to makethe
point that the routers are indeed smart.
IPsec Tunnel Scalability
Based on Ericsson’s Long Term Evolution (LTE)network design
recommendation, IPsec tunnelsshould be setup between base stations
(eNodeB)and the core mobile network. In other words,connectivity
over the backhaul should be encrypted.
In the topology used for the test, the aggregationnetwork
included Ericsson’s SSR 8010 routerequipped with a single IPsec
termination card(called SSC-1). This will be the logical place in
thenetwork to terminate both base station connectivity(before
handing that traffic to the Evolved PacketCore) as well as
residential and business services.
We used Ixia’s PerfectStorm ONE to measure thenumber of IPsec
tunnels that a single SSC-1 linecard could terminate and then
generated traffic forall tunnels. We established 8,000 tunnels
eachusing IKEv2 for key exchange and AES128 fortunnel encryption.
In addition, we also verified thatEricsson RBS could establish a
tunnel to the sameSSR 8010.
Figure 2: IPsec Performance
EANTC Test Report: Ericsson Evolved IP Network Solution 2015
Update – Page 3 of 12
-
Once tunnels were set, we generated traffic in eachof the
tunnels and verified that the router is not onlyadapt at
terminating IPsec tunnels, but also is ableto forward traffic. We
measured 8.16 Gbit/s down-stream and 6.79 Gbit/s upstream of
traffic using afixed frame size of 1368 bytes for payload.
Wemeasured 3.77 Gbit/s downstream and 2.32Gbit/s upstream using a
mix of packet size. TheIPsec test was run using Ericsson’s SSR 14B
GeneralAvailability (GA) code due to performance improve-ments for
IPsec.
BNG Session Activation Rate
Next we focused our attention on the BroadbandNetwork Gateway
(BNG) function residing in thesame Ericsson SSR 8010. The first
aspect tomeasure is the rate with which subscribers could
beactivated. Said rate is an indication of what theservice provider
could expect should all subscribersattempt to start their
DSL-modems at the same timeat home. This is a rare event, however,
when theevent occurs, after a major power failure forexample, it is
a good idea to keep customers happyby allowing as many as possible
to register at thesame time.
As the figure below illustrates, we measured an acti-vation rate
of 300 sessions per second. The perfor-mance was consistent for
both single stack PPPoEsubscribers (i.e. IPv4 only) and dual
stacksubscribers. In the latter case, the BNG assignedboth IPv4 and
IPv6 addresses to the subscriber.
BNG Subscriber Scalability
Once we measured the activation rate, we used thevalue to also
measure the number of subscribers asingle BNG card could support
and then generatedtraffic for each of the subscribers. Here we
enter-tained three subscriber types:
• Single Stack – Customer with only IPv4 addresses.
• Dual Stack – Customers with IPv4/IPv6 addresses.
• Quality of Service – Customers that use IPv4addresses as well
as three classes of service
We were able to reach the advertised number ofSingle Stack
subscribers that Ericsson could support– 96,000. Once all
subscribers were activate wemeasured throughput of 36 Gbit/s.
The number of Dual Stack subscribers we were ableto reach was
48,000 and the test showed that therouter was then able to
demonstrate throughput of24 Gbit/s. The third condition showed the
sameresults.
VPLS Services Scalability
Having investigated two services that traditionallyfocus on
mobile and residential subscribers, weturned our attention to a
business-oriented service:multipoint-to-multipoint layer 2
connectivity. This isthe kind of service that could be realized
using theVirtual Private LAN Services (VPLS) we tested.
A router's MAC address and Virtual Switch Instance(VSI)
capacities will affect the profitability of theoperator's service
offerings. This is because thenumber of services a carrier could
sell to customersinterested in multipoint-to-multipoint
Ethernetservices is limited by these two factors. The latter
istypically limited by the number of end points partici-pating in
the virtual switch domain – more endpoints translates to higher
signaling load on therouter.Figure 3: BNG dual stack session
activation rate
Figure 4: BNG throughput performance
EANTC Test Report: Ericsson Evolved IP Network Solution 2015
Update – Page 4 of 12
-
SSR 8010
We designed the test in such a way that 100protected services
were initiated by the accessdevices (both SP 420) and were joined
by addi-tional sites emulated by the Ixia tester on each SSR8004 in
the aggregation network. We asked Eric-sson to configure a total of
6,000 VPLS instances onfour different routers and then used two
Ixia ports toemulate additional PE routers. This meant that
eachvirtual switch domain included four routers and atotal of
12,000 attachment circuits.
Once the configuration was created (a script-inten-sive
activity) we went through the steps ofmeasuring how quickly the
routers learn MACaddresses and how many MAC addresses could
belearned in total, while also monitoring the CPU loadand memory
usage on all devices under test.
The result was a MAC learning rate of 30,000addresses per second
for a total of 996,000 MACaddresses. This means that for example
all ofOrange Business Services' employees could acti-vate their
devices during the same second andimmediately start working. An
impressive feat for adevice that's designed as a router and is
serving asa switch.
Along the way we discovered a small issue. It wasnot possible to
clear the MAC address tables fromthe command line. Ericsson
explained that thiscommand will be supported in the General
Avail-
ability (GA) code, but as we had an early version ofthe software
it was not supported in that build.
We also observed that while learning took place at30,000 MAC
addresses per second, a few (under10) MAC addresses took a few more
attempts to beinserted into the MAC table. Looking for 10 MACsout
of almost a million is a tedious task which is whywe took note, and
moved on.
Network and Performance Management
A network service life cycle comprises requirementssuch as
service discovery, creation, modificationand trouble shooting. We
reported previously thatEricsson was in the process of replacing
their NMS.For this year's updated test, we had the opportunityto
verify the functionality of Ericsson's IP TransportNetwork
Management System (IPT NMS).
As we were testing service lifecycle management,we allowed
Ericsson to choose the service typeunder test. Ericsson chose
Layer-3 VPN, andexplained this was their primary focus in the
currentNMS. Other services could be managed in parts ofthe network,
but due to the combination of NMSand router software releases being
used the L3VPNwas selected. As the NMS release to support SSR14B
was not yet available, Ericsson needed to usethe SSR 14A
release.
Service Creation
The first step in the test was to create a L3VPNservice
template, and then use this to configure theservice (including BGP
on PE-CE links). The servicespan involved two Ericsson devices: the
SP 420 andSSR 8010. It took less than 5 minutes to create
andconfigure the service. As soon as we activated theservice via
the NMS Graphical User Interface (GUI)the service end points and
the access circuits weresuccessfully provisioned (roughly within
40seconds).
BNG SSC ENET
SSR 8010
Aggregation Core
6,000 VPLS12,000 Attachment circuits 1Million MAC address
8,000 IPsec tunnels
96,000 Single stack OR48,000 Dual stack OR 48,000 QoS
enabled
single stack PPPoE routes
Route Reflector32,000 VPN routes 1,800 BGP label unicast
8,000 L3VPN
Clock synchronizationFrequency offset: up to 3.8 ppbMaximum Time
Error: 155 ns
Access
Figure 5: Multi-Service Support in Ericsson EIN
ENET
SSR 8010SSR 8004
ENET
Multi-Service Capabilities Tests Highlights
Support 96,000 Single Stack Subscribers
Support 48,000 Dual Stack Subscribers
Support 8,000 IPsec tunnels
Measured up to a million MAC addresses
Verified up to 6,000 VPLS instances
EANTC Test Report: Ericsson Evolved IP Network Solution 2015
Update – Page 5 of 12
-
Once a service is created, it may be necessary tomake changes to
it. We extended the same servicethat originally had two end points
by adding athird. This is analogous to a customer asking for
anadditional site to be connected to an existing VPN.Adding another
site required the creation of a newservice based upon the
pre-existing service. Thisseemed like a strange approach to a
service modifi-cation, especially since once we removed the
addi-tional site from the service, the system accepted theremove
request, but reported that the service waspartially deployed. This,
as explained by Ericsson,was because of the difference on the IPT
NMScompared to the active version of that servicerunning on the
routers. Once the configuration waspushed to the routers we
observed the expectedbehaviour.
The next activity in our service life cycle test wasservice
discovery. We already knew that the servicewe created was installed
having sent tester traffic toconfirm that everything behaved as
expected. Weasked Ericsson to tell us if other services
wereinstalled in the network. Ericsson created a
servicereconciliation task and let it loose on the network.The task
quickly returned with the correct informa-tion: 65 L3VPNs were
installed in the network.
Last but not least, we wanted to check the health ofthe service
we created. Ericsson's IPT NMS wasconfigured to monitor all service
end-points usingPing while we configured the tester to send
trafficbetween all end points. The tool reported theaverage latency
for the service and showed all end-points were active. We then
failed one of the accessdevices (emulated by Ixia) and were
immediatelynotified by IPT NMS of the issue. The alarm wasspecific
enough that we knew not only that therewas a problem with the
service, but also exactly
where the problem was (to a slot/port level). Wecould tell that
this was immensely useful yet weasked ourselves what would happen
when a serviceof 1,000 end points had to be monitored. If 1,000ping
pairs would have to be created, then clearlythe usability of the
tool would be limited, unlessanother approach is used.
Network Performance
In the 2014 report we tested two of Ericsson'sEvolved IP Network
products at full scale – the SP420 and the SSR 8010. For this
year's test weturned our attention to Ericsson's newest product
–the SSR 8004.
Alongside the new router, we also expanded ourinvestigation into
one of Ericsson's key productareas: Microwave transport. Ericsson
has deliveredover 3 million MINI-LINKs1, and has a market shareof
25%, which tells us they take their microwaveproducts very
seriously! In this segment of the testswe really looked into
throughput as well as optimi-zation methods.
Figure 6: L3VPN Service Creation Using IPT NMS
1.
http://www.ericsson.com/news/140320-mircowave-milestone_244099438_c
Figure 7: L3VPN Service Monitoring IPT NMS
Network and Performance Management Test Highlights
IPT NMS covers the complete service life cycle
EANTC Test Report: Ericsson Evolved IP Network Solution 2015
Update – Page 6 of 12
http://www.ericsson.com/news/140320-mircowave-milestone_244099438_chttp://www.ericsson.com/news/140320-mircowave-milestone_244099438_c
-
SSR 8004 100GigabitEthernet Performance
For the throughput performance test focusing on theSSR 8004 we
asked Ericsson to mix two line cardswhich we believed to be
representative of therouter’s position in the network:
10GigabitEthernetand 100GigabitEthernet. The logic used for the
testwas that today the 10GbE interfaces will face theaccess
network, while the 100GbE interfaces willface the core network.
The tests followed the traditional IETF-defined RFC2544 for
throughput measurements. Based on yearsof experience we ran the
tests twice – once tomeasure the throughput using 30 second tests
andthen, using the values collected in the short test run,repeated
the tests at each frame size for 10minutes. We expected the
results, based on thenumber of ports in the test, to be
400Gbit/sthroughput with latency in the order of tens of
micro-seconds.
Before the tests started Ericsson explained that ourexpectations
may not be accurate. As a conse-quence of their design choices on
these line cardsEricsson, does not consider wirespeed forwardingof
smallest packet sizes as a realistic real world usecase.
Our tests confirmed Ericsson’s statements. We wereable to
measure line rate performance at packetsizes of 373 and 1,518 bytes
(with latencies of 43and 51 microseconds respectively), but for
thesmaller packet sizes of 70 and 128 bytes, wemeasured 53 and 81
percent of theoretical linerate.
We also ran one test with a mix of packet sizes(called IMIX).
Here the tester is configured to send aseries of packet sizes with
varying weights. Sinceour IMIX was heavily weighted towards
smallpacket sizes (72% of the packets were smaller than256 bytes)
we were only slightly surprised to seethat we could reach 96.87% of
line rate. We alsoobserved that latency increased in this test case
byup to 1,046 microseconds. Ericsson explained thatthe increase in
latency was due to larger packetsdelaying the transmission of
smaller packets placedbehind them in the queues.
MINI-LINK Throughput
One way to think about the MINI-LINK microwavetransport solution
is as an Ethernet switch, wheresome of the interfaces are not
implemented withcopper or fiber. Instead they are based on a
radiointerface that brings new challenges switches do notnormally
face, yet must still perform as any otherswitch would be expected
to in a transport network.To measure the performance of the switch
part ofthe MINI-LINK we ignored the microwave interfacesand
connected all 8 GigabitEthernet ports to thetester and ran the same
standard RFC-basedthroughput test we ran with the Ericsson SSR
8004.
We used the same packet sizes and the same dura-tion and
received full line rate results for all fixedframe size tests of 30
seconds duration. Whenrepeating the tests with IMIX traffic, we
measured66.65% of total line rate or 5.25 Gbit/sthroughput. In this
case we also measured increasein latency from 515 ms for 1518 byte
packets to996 ms.
We repeated the test for 10 minutes to verify thatthe switch
will be stable over longer operationalperiods. In this condition,
for each of the framesizes (fixed and IMIX), we recorded minimal
packetloss of 0.001%.
Figure 8: Ericsson SSR 8004 in the test
EANTC Test Report: Ericsson Evolved IP Network Solution 2015
Update – Page 7 of 12
-
Microwave Deep Buffers
The majority of the traffic on the internet today runsover TCP,
which utilizes flow control and congestioncontrol mechanisms in
order to provide reliable end-to-end transport. TCP is a demanding
protocol - ittries to maximize the amount of throughput itreceives.
Should TCP detect packet loss, it backs upby 50% and slowly tries
again.
Microwave links in networks therefore run the risk ofbecoming a
bottleneck, as even if a network hasbeen designed to take into
account available linkbandwidth, congestion can occur due to
adaptivemodulation changes (for example caused by heavyrain). To
cope with this, Microwave devices shouldbe capable of buffering
sufficient frames to be ableto continue sending until the sender
receives a TCPacknowledgement.
Ericsson explained that the MINI-LINK PT productshave up to 8
megabytes of buffer to maximizemicrowave link utilization. In this
test we measuredthe benefits of these buffers on end-to-end
TCPthroughput. As HTTP traffic was used for this test,we used the
correct 'goodput' term to indicateapplication level throughput.
In the test setup we created a microwave hop usingtwo MINI-LINK
PT, then connected an Ixia port toeach device. We configured a
large HTTP object of2 gigabytes and asked Ericsson to use the
highestmicrowave modulation of 1024 QAM. We expectthe link, with
its 100 ms round trip time, to provideus with 435Mbit/s of
goodput.
Initially we configured the microwaves with a tradi-tional small
buffer size of 168 Kb. The goodput wewere able to measure was 308
Mbit/s. Once westarted increasing the buffer to 1 Mb and then
1.4Mb, we measured 388 and 435 Mbit/s respec-tively. Increasing the
buffer beyond 1.4 Mb led tono further improvement in goodput for
our testsetup, as at this point the buffer depth was sufficientfor
the round trip time.
Reducing the amount of memory in order to attemptto push down
the price of a device, as well aslatency, may be common practice,
but not for Eric-sson. As everything in life, there are tradeoffs
to bemade. The trade-off in the case of reducing latencyand memory
can lead to a false economy whenconsidering LTE and LTE-Advanced
deployments.These require not only ever-increasing bandwidth,
but also ever-increasing goodput. It is thereforeimportant to
consider the end-to-end transport solu-tion including microwave, in
order to deliver thequality of experience subscribers are looking
for.
Microwave multi-layer header compression
Another method to squeeze more bandwidth from anetwork link is
to compress the traffic itself. Ericssonhas implemented multi-layer
header compression intheir microwave products and asked us to test
theMINI-LINK PT 2020 to verify that compression reallyprovides
meaningful performance improvements.The compression method used
here is multi-layersince it compresses headers such as Ethernet,
MPLSand IP. Ericsson claims that this compression willhave the
greatest impact in mobile networks sincethe payload itself is
likely to be compressed orencrypted by other elements in the
network.
From a testing perspective, the use case was simple.We generated
bidirectional traffic across a micro-wave link and ran the test
with and without thecompression feature enabled. We also used
twosets of traffic conditions, an internet mix of packetsizes
ranging from 64 bytes to 1518 bytes (with72% of the packets being
smaller than 129 Bytes)and the second with only 82 bytes where
weexpected to see a bigger impact due to the ratio ofheader to
payload size.
We expected to see more throughput in both cases,but just how
much was unclear. While throughputwithout compression showed 457
Mbit/s across themicrowave link, throughput with the Internet
mixtraffic improved by only 1% to 462 Mbit/s. Theimprovement was
however huge for the smallpacket size – 18% to 542 Mbit/s. The
reason for
Figure 9: Goodput Results with 1.4 Mb Microwave Buffer
EANTC Test Report: Ericsson Evolved IP Network Solution 2015
Update – Page 8 of 12
-
the difference was obvious. An MPLS packet size of82 bytes
includes 4 bytes of MPLS headers as wellas 20 bytes of IP headers
and 8 bytes of UDPheader. This means that 39% of the packet size
isheaders. As we demonstrated, these headers couldbe compressed and
since such a large portion ofthe packet is headers, the gain of
compression ispronounced.
Compression for mobile traffic could take place intwo locations
in the network – in the access andafter the Evolved Packet Core (on
the SGi-interface).Ericsson argues that application acceleration
shouldbe used on the SGi-interface while Microwavecompression,
agnostic to the traffic payload, is thebest way to achieve
efficiency in a mobile accessnetwork.
Network Availability
It seems that every test we ever execute includeshigh
availability test cases. This is an indication ofhow important
networks have become to our lives,hence operators' sensitivity to
high availabilityperformance. These days, with so many
criticalbusinesses operating on the Internet, we simply cannot
afford to lose connectivity and hence want thenetwork to be as
robust as possible.
We had already successfully tested IP Fast Rerouteon the SSR
routers, Bidirectional Fault Detection(BFD) between the SSR and SP
routers, as well asgraceful restart on the SSR in the 2014 activity
-therefore we chose to focus this time on new capa-bilities of the
Evolved IP Network solution.
IP Fast Reroute: Loop Free Alternates on SSR
Despite all of the success that MPLS has seen in thelast 15
years, some argue that the protocol stackhas become too bloated. To
operate an MPLSnetwork with all its bells and whistles, one
mustdeploy RSVP-TE, an IGP, BGP, and label distributionprotocol
(LDP). In recent years the IETF has beenstudying if there is a way
to reduce this list withoutlosing capabilities.
IP Fast Reroute is part of the answer to this question.The goal
of the RFCs that define IP Fast Reroute is to“reduce failure
reaction time to 10s of millisec-onds...” (RFC 5286), and achieve
this without theuse of RSVP-TE by simply pre-computing an
alter-nate next-hop that is activated when the primarynext-hop
fails.
Ericsson explained that at the time of the testing thefeature
was only available on the SSRs which iswhy we focused our attention
on the aggregationnetwork and emulated the failure between SSR8004
and 8010. We ensured that no RSVP configu-ration was in use on
these routers while weexecuted the test, only MPLS with LDP fed
from IS-IS.
We emulated two failure scenarios in the test:optical layer
failure in which BFD was used todetect the issue and the
traditional loss of signalfailure. Each failure scenario ran three
times testingboth failure and recovery.
In the test runs which used BFD to detect the failurewe measured
107 to 111 ms out of service timebetween test runs. This certainly
was an impres-sively consistent result. In all recovery tests we
alsorecorded some out of service times in the range of19 to 27
ms.
In the tests that used loss of signal to detect failurewe
measured 6 to 24 ms of service disruption.Again, during the
recovery phase we measured upto 6 ms service impact.
Ericsson explained that the BFD times should havebeen much lower
(as seen in the previous report),however, a bug in the pre-release
software that wewere using meant that BFD-detected failures werenot
triggered as quickly as the loss-of-signal usecase. This bug was
known before the test was run,and Ericsson confirmed it is fixed in
the GA soft-ware version.
LFA tool
Together with the other service life-cycle tools wediscussed,
Ericsson demonstrated an off-line IP FastReroute (FRR) Loop-free
Alternate (LFA) analyzer,which is integrated with Ericsson's NetOp
EMS.Using this GUI, we created a ring network topologywith four
nodes, LFA converge metric, non-protectedroutes as well as links
for the destination nodes. Thetool allowed us to look into “what
if” scenarios,identify where in the topology potential
resiliency
Network Performance Tests Highlights
100GigabitEthernet line rate for 373 and 1518 bytes packet
size
Up to 25% improvement in Microwave link utilization through
compression
EANTC Test Report: Ericsson Evolved IP Network Solution 2015
Update – Page 9 of 12
-
bottlenecks would occur, as well as providesuggested optimized
topologies.
RSVP on SP 400
In the previous report we tested the failure in theaggregation
and core networks. This time wefocused our attention on the access
network. SinceEricsson added support for Resource
ReservationProtocol - Traffic Engineering (RSVP-TE) in its SP
400devices they could now protect MPLS tunnels origi-nating in the
cell site routers. We were more thanhappy to oblige in testing this
functionality.
Ericsson chose to configure static backup tunnelswith explicit
routes which, if one is looking toadhere strictly to our industry's
nomenclature,means that the test was not verifying RSVP-TE
FastReroute. Still, the test verified the solution's ability
toprotect MPLS tunnels in the access network.
We chose a link between the Ericsson SP 420 andthe SSR 8004 and
disconnected it while traffic wasflowing for one of our services.
We then measuredthe out of service time based on the number of
packets that were missing and verified that theservice indeed
returned to normal operation. Werepeated the test three times in
order to rule outoutliers.
The results satisfied Ericsson’s expectations. In theupstream
direction the highest measured out ofservice time was 256 ms with
the lowest being 248ms. In the downstream direction we
measuredbetween 127 and 84 ms out of service time.
We also evaluated if a recovery from the failurewould result in
service disruption. We reconnectedthe link between the Ericsson SP
420 and the SSR8004. No packet loss was observed at all in
thedownstream direction. In the upstream direction,leaving the SP
420 towards the SSR 8004, amaximum out of service time of 89 ms
wasrecorded. Ericsson explained that the minimal lossof traffic,
which was expected (as per the test plan),was the result of
hardware differences between theSP 420 and the SSR 8004.
LTE-A Readiness
In our 2014 test we spent a great deal of reportingreal estate
on clock synchronization. We demon-strated that the Ericsson
Evolved IP Network solutionwas ready to support Long Term Evolution
(LTE)deployment and included not only clock accuracy,but also clock
robustness.
That was 2014. The conversation amongst mobileoperators has
moved on to the higher capacitiesand lower latency that both
LTE-Advanced and 5Gare promising. For these the importance of
clockaccuracy, stability, and robustness become evermore
pronounced. Ericsson was eager to demon-strate that their Evolved
IP Network solution is morethan capable of meeting such
requirements.
There is a plethora of new aspects in these tests.Since the
tests were performed at EANTC's lab,where, at the time, both
Microsemi and Meinberghad GrandMaster clocks installed, Ericsson
wasable to demonstrate a dual-grandmaster clockstrategy. Each test
performed in this section was
Figure 10: Network topology before optimization
Figure 11: Optimized topology for link protection
Network Availability Tests Highlights
Loop Free Alternates in Ericsson SSR supported
RSVP convergence of up to 256 ms in SP 420
EANTC Test Report: Ericsson Evolved IP Network Solution 2015
Update – Page 10 of 12
-
executed twice, once using the Meinberg LANTIMEM3000 as clock
source and again with theMicrosemi 2700 GrandMaster.
Ericsson explained that to enable IEEE 1588 on theSSR requires
only an updated version of the ALSW(Alarm and Switch Fabric) card.
The card can beupgraded in-service without disruption to anexisting
network. All SSRs required to distributeclocking information were
equipped with this newcard (ALSW-T), so what did we actually
test?
Full Path End-to-End Clock Synchronization
Full path timing support is defined as each node inthe network
playing a role in the clock deliveryservice. In Ericsson's case
that meant all routers andmicrowave devices between the
GrandMasterclocks and the RBS were configured to function as
aBoundary Clock.
In line with ITU-T G.8273.2, Ericsson configuredtheir devices to
use physical layer frequencysupport from Synchronous Ethernet, with
phaseinformation distributed using the Precision TimeProtocol (PTP)
profile specified by G.8275.1. Thegoals for the test were in line
with the standards andfrequency deviation of no more than 16 parts
perbillion (ppb) with phase error within ±1.1 s. Thestandards
actually call for phase error limits within±1.5 s, but Ericsson
explained that the additional400 nanoseconds is an air interface
budget.
We ran the test without any traffic in the network for15 minutes
once the slave clock showed a lockstate. The results of this test,
which we consideredas baseline, were great. The frequency
offsetranged between 1.6 and 3.8 ppb. The maximumtime error ranged
between 124 and 155 nanosec-onds – an order of magnitude better
than expected.
Long Term Clock Stability
After the baseline test was completed we movedtowards a more
realistic test case, as no network isexpected to run without
traffic. This time we usedthe industry standard measurement
guidelines fromITU-T G.8261 to generate traffic in the network.
Weused the two most often referenced test cases, 12and 13, and ran
the tests for more than 1 hour andmore than 14 hours
respectively.
We measured frequency offset of at most 6.56 ppband maximum time
error of up to 157 nanosec-onds. The change between a 'clean'
network and anetwork with emulated traffic was therefore
almostnon-existent, highlighting the benefit of the fulltiming
support model.
Clock Robustness
Now that we have seen how the network works innormal conditions,
we asked Ericsson to demon-strate what happens when the network is
experi-encing failure. In our network there were twoobvious failure
scenarios – a failure in the linksbetween the routers and a failure
caused by micro-
Figure 12: Packet Clock Synchronization – Full Path Support
GPS
RBS 6501
Antenna
Microwave Link 10 Gigabit Ethernet1 Gigabit Ethernet
1PPS LinkClock ReferencePTP Distribution Path SyncE Distribution
Path
Access Aggregation Core
SSR 8010
MINI-LINK TN
Grandmaster12:50:00Clock Link — Freq.
Boundary Clock
SSR 8010
SSR 8010SP 415 SP 420
SP 420 SSR 8004
SSR 8004
SSR 8010
Meinberg LANTIME M300012:50:00
Ixia Anue 3500 Frequency/Phase Analyzer
Microsemi TimeProvider 2700 12:50:00
EANTC Test Report: Ericsson Evolved IP Network Solution 2015
Update – Page 11 of 12
-
wave nodes losing their air interface. Bothscenarios require
that the last node implements afunction called holdover which
allows the node tocontinue delivering a clock signal
withoutannouncing to the world “I am lost!” andsuppressing the
clock output altogether.
This year we also had a small cell radio basestation from
Ericsson, the multi-standard outdoormicro base station known as RBS
6501, whichparticipated in the packet clock distribution
infra-structure and was in fact the last node in the chain.While we
could not measure the clock quality onthe mobile air interface (for
lack of instrumentation)we did verify that the RBS was reporting a
lock tothe clock signal during all of the test runs, provingthat it
remained locked while the transport networkwas in a holdover
state.
The first scenario investigated the microwavefailure. Here we
simply disconnected the RF cablesbetween the two antennas while
measuring theclock quality. We also verified that the devicesnever
reported “Free-running” state.
Shutting off the Microwave link actually meant thatthe SP
router, positioned in front of the microwaverouter had to perform
the hold over function. In bothtest scenarios (i.e. with both
GrandMaster clocks)we were able to measure frequency deviation of
atmost 6.12 ppb. The maximum time error recordedwas 191.2
nanoseconds.
We also used this opportunity to investigate whathappens when
the microwave was not completelyturned off, but the frequency
modulation wasreduced. We used an attentuator to repeat the
testtwice: once with 512 QAM and once with 16QAM. Both tests showed
that the clock signal wasnot affected by modulation changes and the
valuesrecorded were along the lines of all other tests.
The results of the link failure between the SP 420and the SSR
8004, the last failure condition wemeasured, were similar to the
above. The maximumtime error we recorded was - 309
nanoseconds.Again, the RBS reported remaining locked, andnone of
the devices went into holdover mode.
Ericsson Evolved IP Network Solution Tests Summary
We applaud Ericsson’s commitment to continuoussolution
development and independent validation.We are also pleased to see
the Evolved IP Networksolution continue to progress and report
success inthe market.
With this updated report we can confirm that Eric-sson’s Smart
Services Router (SSR) lives up to itsname and is capable of
delivering truly convergedand concurrent multi-services such as
BNG, IPsec,Ethernet and IP/MPLS.
Multi-service is not the only capability highlightedhere, but is
a critical element in Ericsson’s commit-ment to being a dependable
solution to their serviceprovider customers as they grow their
networks.Looking at the clock synchronization results as wellas the
integration of the base station with the trans-port infrastructure,
we get a definite sense that Eric-sson is planning to provide their
customers with averified solution that anticipates the
challengesinvolved with 3GPP and 5G migration.
About EANTC
The European AdvancedNetworking Test Center(EANTC) offers
vendor-neutral network test servicesfor manufacturers,
serviceproviders and enterprisecustomers. Primary businessareas
include interopera-bility, conformance and
performance testing for IP, MPLS, Mobile Backhaul,VoIP, Carrier
Ethernet, Triple Play, and IP applications.
EANTC AGSalzufer 14, 10587 Berlin, [email protected],
http://www.eantc.com/vF1.1 20150315, JG
LTE-A Readiness Tests Highlights
Phase accuracy consistently under 310 nanoseconds including
failover scenarios
Full on-path clock synchronization support
Microwave adaptive modulation does not affect clock
performance
EANTC Test Report: Ericsson Evolved IP Network Solution 2015
Update – Page 12 of 12
EricssonEvolved IP Network Solution 2015 UpdateMulti-Service,
LTE-A Readiness and Converged Transport ReportBackgroundTested
DevicesTest EquipmentMulti-Service CapabilitiesIPsec Tunnel
ScalabilityBNG Session Activation RateBNG Subscriber
ScalabilityMulti-Service Capabilities Tests HighlightsNetwork and
Performance Management
Service CreationNetwork and Performance Management Test
HighlightsNetwork Performance
SSR 8004 100GigabitEthernet PerformanceMINI-LINK
ThroughputMicrowave Deep BuffersNetwork Performance Tests
HighlightsNetwork Availability
IP Fast Reroute: Loop Free Alternates on SSRLFA toolRSVP on SP
400Network Availability Tests HighlightsLTE-A Readiness
Full Path End-to-End Clock SynchronizationLong Term Clock
StabilityClock RobustnessLTE-A Readiness Tests HighlightsEricsson
Evolved IP Network Solution Tests SummaryAbout EANTC